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Full vulnerability report · 2026
CVE-2026-84640High confidence

One byte overflow read in mail parser

Mozilla · Thunderbird

7.5HighCVSS 3.1
Recommended action
Patch only the product branches with a verified fix

High technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 0.26% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Mozilla Thunderbird and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 30 daysRemediation target: Within 180 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Cross-source reconciliation

Remediation availability differs by product scope

Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Distribution package intelligence

Release-specific package status

Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

5 package states
Package result overrides the generic status

BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 1 affected package state shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.

Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Distribution releaseSource packageVendor stateFixed versionEvidence
Debian trixietrixie · sourcethunderbirdVendor fix publishedDebian records a fixed source-package version for this release.1:140.15.0esr-1~deb13u1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian bookwormbookworm · sourcethunderbirdVendor fix publishedDebian records a fixed source-package version for this release.1:140.15.0esr-1~deb12u1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian forkyforky · sourcethunderbirdAffected, no fix publishedDebian currently tracks this release as open.Not published in this feedDebian Security Tracker ↗Source updated 6 Oct 2026
Debian sidsid · sourcethunderbirdVendor fix publishedDebian records a fixed source-package version for this release.1:153.2.0esr-1Debian Security Tracker ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archivethunderbirdUnder evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical Ubuntu Security ↗Source updated 5 Oct 2026
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

2 current
CVE-2026-84640 · CSAF 2.0 · revision 7 · interimSUSE Product Security TeamCVE-2026-84640
80 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • MozillaFirefox as component of SUSE Linux Enterprise High Performance Computing 12 SP5
  • MozillaFirefox-devel as component of SUSE Linux Enterprise High Performance Computing 12 SP5
  • MozillaFirefox-translations-common as component of SUSE Linux Enterprise High Performance Computing 12 SP5
  • MozillaFirefox as component of SUSE Linux Enterprise High Performance Computing 15 SP1
  • MozillaFirefox-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP1
  • MozillaFirefox-translations-common as component of SUSE Linux Enterprise High Performance Computing 15 SP1
  • MozillaFirefox-translations-other as component of SUSE Linux Enterprise High Performance Computing 15 SP1
  • MozillaFirefox as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • MozillaFirefox-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • MozillaFirefox-translations-common as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • MozillaFirefox-translations-other as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • MozillaFirefox as component of SUSE Linux Enterprise High Performance Computing 15 SP3
Summary
A maliciously constructed mail header could lead to a one byte read past the end of a buffer. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
Remediation
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
CVE-2026-84640 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitythunderbird: One byte overflow read in mail parser
5 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • rhel10/thunderbird-flatpak as a component of Red Hat Enterprise Linux 10
  • thunderbird as a component of Red Hat Enterprise Linux 6
  • thunderbird.src as a component of Red Hat Enterprise Linux 6
  • thunderbird as a component of Red Hat Enterprise Linux 7
  • thunderbird.src as a component of Red Hat Enterprise Linux 7
Summary
A flaw was found in Thunderbird. A remote attacker could exploit this vulnerability by sending a maliciously constructed mail header. This could lead to a one-byte read past the end of a buffer, potentially resulting in information disclosure or other unpredictable behavior.
Remediation
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-69709

No EUVD known-exploited evidence

A maliciously constructed mail header could lead to a one byte read past the end of a buffer. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
7.5 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch only the product branches with a verified fix

High technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
01

What, why and how

A maliciously constructed mail header could lead to a one byte read past the end of a buffer. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

What

A maliciously constructed mail header could lead to a one byte read past the end of a buffer. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

Why

The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations after the targeted buffer.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

A maliciously constructed mail header could lead to a one byte read past the end of a buffer. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

Why

The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations after the targeted buffer.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Buffer Over-read → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-126 ↗

CWE-126: Buffer Over-read. The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations after the targeted buffer.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.INoneIntegrity impact: No direct loss is represented by this metric.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-126
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-69709Official EUVD mapping

A maliciously constructed mail header could lead to a one byte read past the end of a buffer. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

Official EUVD record ↗
BSI · German · WID-SEC-2026-3132Mozilla Firefox und Thunderbird: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Mozilla Firefox und Thunderbird ausnutzen, um Berechtigungen zu erweitern, Sicherheitsmaßnahmen zu umgehen, sensible Informationen offenzulegen, Daten zu manipulieren, Spoofing-Angriffe durchzuführen, möglicherweise durch Speicherbeschädigungen beliebigen Code auszuführen oder Denial-of-Service-Zustände herbeizuführen.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-1106Multiples vulnérabilités dans les produits Mozilla

d?id=CVE-2026-84139 Référence CVE CVE-2026-84140 https://www.cve.org/CVERecord?id=CVE-2026-84140 Référence CVE CVE-2026-84141 https://www.cve.org/CVERecord?id=CVE-2026-84141 Référence CVE CVE-2026-84142 https://www.cve.org/CVERecord?id=CVE-2026-84142 Référence CVE CVE-2026-84143 https://www.cve.org/CVERecord?id=CVE-2026-84143 Référence CVE CVE-2026-84144 https://www.cve.org/CVERecord?id=CVE-2026-84144 Référence CVE CVE-2026-84145 https://www.cve.org/CVERecord?id=CVE-2026-84145 Référence CVE CVE-2026-84637 https://www.cve.org/CVERecord?id=CVE-2026-84637 Référence CVE CVE-2026-84639 https://www.cve.org/CVERecord?id=CVE-2026-84639 Référence CVE CVE-2026-84640 https://www.cve.org/CVERecord?id=CVE-2026-84640 Référence CVE CVE-2026-84641 https://www.cve.org/CVERecord?id=CVE-2026-84641 Référence CVE CVE-2026-84642 https://www.cve.org/CVERecord?id=CVE-2026-84642 Gestion détaillée du document le 02 septembre 2026 Version initiale Alertes Avis Bulletins d’actualités Mentions légales Conditions générales À propos Contact cyber.gouv.fr service-public.fr legifrance.gouv.fr info.gouv.fr france.fr info.gouv.fr/risques Premier Ministre / Secrétariat Général de la Défense et de la Sécurité Nationale / Agence nationale de la sécurité des systèmes d'information

Official advisory ↗
CSIRT Italia · Italian · risolte-vulnerabilita-in-prodotti-mozilla-9Risolte vulnerabilità in prodotti Mozilla

Aggiornamenti di sicurezza sanano 11 vulnerabilità, di cui 3 con gravità “critica” e 8 con gravità “alta”, nei prodotti Firefox, Firefox ESR, Thunderbird.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-031862Mozilla FoundationのMozilla Thunderbirdにおけるバッファオーバーリードの脆弱性

悪意を持って細工されたメールヘッダーにより、バッファの末尾を1バイト超えて読み取られる可能性があります。この脆弱性はThunderbird 155、Thunderbird 140.15、およびThunderbird 153.2で修正されました。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix availability varies by product
Affected
Fixed
Thunderbird: 140.15 ≤ 140.*, 153.2 ≤ 153.*, 155 ≤ *
Action
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
Official vendor articles6 stored documents

Linked articles are downloaded and versioned as source evidence. A CVE mention or approved update relationship does not, by itself, verify a fix for every product branch.

  • Security Vulnerabilities fixed in Thunderbird 155 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 26 Sep 2026Security Vulnerabilities fixed in Thunderbird 155 Announced September 1, 2026 Impact high Products Thunderbird Fixed in Thunderbird 155 In general, these flaws cannot be exploited through email in the Thunderbird product because scripting is disabled when reading mail, but are potentially risks in browser or bro
  • Security Vulnerabilities fixed in Thunderbird 140.15 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 26 Sep 2026Security Vulnerabilities fixed in Thunderbird 140.15 Announced September 1, 2026 Impact high Products Thunderbird Fixed in Thunderbird 140.15 In general, these flaws cannot be exploited through email in the Thunderbird product because scripting is disabled when reading mail, but are potentially risks in browser
  • Security Vulnerabilities fixed in Thunderbird 153.2 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 26 Sep 2026Security Vulnerabilities fixed in Thunderbird 153.2 Announced September 1, 2026 Impact high Products Thunderbird Fixed in Thunderbird 153.2 In general, these flaws cannot be exploited through email in the Thunderbird product because scripting is disabled when reading mail, but are potentially risks in browser or
  • Security Vulnerabilities fixed in Thunderbird 155 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 26 Sep 2026Security Vulnerabilities fixed in Thunderbird 155 Announced September 1, 2026 Impact high Products Thunderbird Fixed in Thunderbird 155 In general, these flaws cannot be exploited through email in the Thunderbird product because scripting is disabled when reading mail, but are potentially risks in browser or bro
  • Security Vulnerabilities fixed in Thunderbird 140.15 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 26 Sep 2026Security Vulnerabilities fixed in Thunderbird 140.15 Announced September 1, 2026 Impact high Products Thunderbird Fixed in Thunderbird 140.15 In general, these flaws cannot be exploited through email in the Thunderbird product because scripting is disabled when reading mail, but are potentially risks in browser
  • Security Vulnerabilities fixed in Thunderbird 153.2 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 26 Sep 2026Security Vulnerabilities fixed in Thunderbird 153.2 Announced September 1, 2026 Impact high Products Thunderbird Fixed in Thunderbird 153.2 In general, these flaws cannot be exploited through email in the Thunderbird product because scripting is disabled when reading mail, but are potentially risks in browser or
04

Evidence and provenance

Published 1 Sept 2026 · Last source change 2 Sept 2026, 18:48 UTC · CWE-126 · Buffer Over-read

CVE recordCVE.org · 5.2
CVSS sourceCISA ADP
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-09-02
European sourceENISA EUVD · EUVD-2026-69709
Product sourceVendor CSAF · SUSE Product Security Team
Remediation sourceVendor CSAF · SUSE Product Security Team
CWE sourceCISA ADP
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    rhel10/thunderbird-flatpak as a component of Red Hat Enterprise Linux 10; thunderbird as a component of Red Hat Enterprise Linux 6; thunderbird.src as a component of Red Hat Enterprise Linux 6; thunderbird as a component of Red Hat Enterprise Linux 7; thunderbird.src as a component of Red Hat Enterprise Linux 7; thunderbird as a component of Red Hat Enterprise Linux 8; thunderbird.src as a component of Red Hat Enterprise Linux 8 · Fixed: thunderbird-0:140.16.0-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-0:140.16.0-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-0:140.16.0-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-0:140.16.0-1.el10_2.src as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-0:140.16.0-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debuginfo-0:140.16.0-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debuginfo-0:140.16.0-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debuginfo-0:140.16.0-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debuginfo-0:140.16.0-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debugsource-0:140.16.0-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debugsource-0:140.16.0-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debugsource-0:140.16.0-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debugsource-0:140.16.0-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-0:140.16.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.src as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:140.16.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:140.16.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:140.16.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:140.16.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:140.16.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:140.16.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:140.16.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:140.16.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
    After
    rhel10/thunderbird-flatpak as a component of Red Hat Enterprise Linux 10; thunderbird as a component of Red Hat Enterprise Linux 6; thunderbird.src as a component of Red Hat Enterprise Linux 6; thunderbird as a component of Red Hat Enterprise Linux 7; thunderbird.src as a component of Red Hat Enterprise Linux 7 · Fixed: thunderbird-0:140.16.0-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-0:140.16.0-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-0:140.16.0-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-0:140.16.0-1.el10_2.src as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-0:140.16.0-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debuginfo-0:140.16.0-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debuginfo-0:140.16.0-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debuginfo-0:140.16.0-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debuginfo-0:140.16.0-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debugsource-0:140.16.0-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debugsource-0:140.16.0-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debugsource-0:140.16.0-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debugsource-0:140.16.0-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-0:140.16.0-1.el8_10.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 8); thunderbird-0:140.16.0-1.el8_10.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 8); thunderbird-0:140.16.0-1.el8_10.s390x as a component of Red Hat Enterprise Linux AppStream (v. 8); thunderbird-0:140.16.0-1.el8_10.src as a component of Red Hat Enterprise Linux AppStream (v. 8); thunderbird-0:140.16.0-1.el8_10.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 8); thunderbird-debuginfo-0:140.16.0-1.el8_10.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 8); thunderbird-debuginfo-0:140.16.0-1.el8_10.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 8); thunderbird-debuginfo-0:140.16.0-1.el8_10.s390x as a component of Red Hat Enterprise Linux AppStream (v. 8); thunderbird-debuginfo-0:140.16.0-1.el8_10.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 8); thunderbird-debugsource-0:140.16.0-1.el8_10.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 8); thunderbird-debugsource-0:140.16.0-1.el8_10.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 8); thunderbird-debugsource-0:140.16.0-1.el8_10.s390x as a component of Red Hat Enterprise Linux AppStream (v. 8); thunderbird-debugsource-0:140.16.0-1.el8_10.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 8); thunderbird-0:140.16.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.src as a component of Red Hat Enterprise Linux AppStream (v. 9); and 9 more
    Red Hat Product Security ↗
  2. Affected versionsThe structured affected or fixed version information changed.
    Before
    rhel10/thunderbird-flatpak as a component of Red Hat Enterprise Linux 10; thunderbird as a component of Red Hat Enterprise Linux 10; thunderbird.src as a component of Red Hat Enterprise Linux 10; thunderbird as a component of Red Hat Enterprise Linux 6; thunderbird.src as a component of Red Hat Enterprise Linux 6; thunderbird as a component of Red Hat Enterprise Linux 7; thunderbird.src as a component of Red Hat Enterprise Linux 7; thunderbird as a component of Red Hat Enterprise Linux 8; thunderbird.src as a component of Red Hat Enterprise Linux 8 · Fixed: thunderbird-0:140.16.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.src as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:140.16.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:140.16.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:140.16.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:140.16.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:140.16.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:140.16.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:140.16.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:140.16.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
    After
    rhel10/thunderbird-flatpak as a component of Red Hat Enterprise Linux 10; thunderbird as a component of Red Hat Enterprise Linux 6; thunderbird.src as a component of Red Hat Enterprise Linux 6; thunderbird as a component of Red Hat Enterprise Linux 7; thunderbird.src as a component of Red Hat Enterprise Linux 7; thunderbird as a component of Red Hat Enterprise Linux 8; thunderbird.src as a component of Red Hat Enterprise Linux 8 · Fixed: thunderbird-0:140.16.0-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-0:140.16.0-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-0:140.16.0-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-0:140.16.0-1.el10_2.src as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-0:140.16.0-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debuginfo-0:140.16.0-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debuginfo-0:140.16.0-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debuginfo-0:140.16.0-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debuginfo-0:140.16.0-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debugsource-0:140.16.0-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debugsource-0:140.16.0-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debugsource-0:140.16.0-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-debugsource-0:140.16.0-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); thunderbird-0:140.16.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.src as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:140.16.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:140.16.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:140.16.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:140.16.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:140.16.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:140.16.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:140.16.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:140.16.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
    Red Hat Product Security ↗
  3. Vendor guidanceAuthoritative vendor guidance changed from remediation: access.redhat.com/CVE-2026-84640 to remediation: access.redhat.com/CVE-2026-84640.
    Before
    remediation: access.redhat.com/CVE-2026-84640
    After
    remediation: access.redhat.com/CVE-2026-84640
    Red Hat Product Security ↗
  4. Remediation statusRemediation status changed from Awaiting fix to Patch available.
    Before
    Awaiting fix
    After
    Patch available
    Red Hat Product Security ↗
  5. Affected versionsThe structured affected or fixed version information changed.
    Before
    rhel10/thunderbird-flatpak as a component of Red Hat Enterprise Linux 10; thunderbird as a component of Red Hat Enterprise Linux 10; thunderbird.src as a component of Red Hat Enterprise Linux 10; thunderbird as a component of Red Hat Enterprise Linux 6; thunderbird.src as a component of Red Hat Enterprise Linux 6; thunderbird as a component of Red Hat Enterprise Linux 7; thunderbird.src as a component of Red Hat Enterprise Linux 7; thunderbird as a component of Red Hat Enterprise Linux 8; thunderbird.src as a component of Red Hat Enterprise Linux 8; thunderbird as a component of Red Hat Enterprise Linux 9; thunderbird.src as a component of Red Hat Enterprise Linux 9
    After
    rhel10/thunderbird-flatpak as a component of Red Hat Enterprise Linux 10; thunderbird as a component of Red Hat Enterprise Linux 10; thunderbird.src as a component of Red Hat Enterprise Linux 10; thunderbird as a component of Red Hat Enterprise Linux 6; thunderbird.src as a component of Red Hat Enterprise Linux 6; thunderbird as a component of Red Hat Enterprise Linux 7; thunderbird.src as a component of Red Hat Enterprise Linux 7; thunderbird as a component of Red Hat Enterprise Linux 8; thunderbird.src as a component of Red Hat Enterprise Linux 8 · Fixed: thunderbird-0:140.16.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.src as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:140.16.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:140.16.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:140.16.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:140.16.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:140.16.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:140.16.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:140.16.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:140.16.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:140.16.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
    Red Hat Product Security ↗
  6. Vendor guidanceAuthoritative vendor guidance changed: added vendor advisory: mozilla.org/mfsa2026-86; added vendor advisory: mozilla.org/mfsa2026-87; 1 further additions.
    Before
    remediation: bugzilla.mozilla.org/show_bug.cgi?id=2063964
    After
    remediation: bugzilla.mozilla.org/show_bug.cgi?id=2063964 · vendor advisory: mozilla.org/mfsa2026-86 · vendor advisory: mozilla.org/mfsa2026-87 · 1 more references
    security@mozilla.org ↗
  7. SeveritySeverity changed from Unknown to High.
    Before
    Unknown
    After
    High
    CISA ADP ↗
  8. CVSS scoreCVSS score changed from not recorded to 7.5 (CVSS 3.1 · CISA ADP · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).
    Before
    not recorded
    After
    7.5 (CVSS 3.1 · CISA ADP · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N)
    CISA ADP ↗
  9. ENISA EUVD mappingEUVD-2026-69709 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-69709"}
    ENISA EUVD ↗
  10. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-69709↗Vendor CSAF · SUSE Product Security Team↗Vendor advisory↗Vendor advisory↗Vendor advisory↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-84640 · cve.blacktree.nl