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Full vulnerability report · 2026
CVE-2026-109756High confidence

Privilege escalation in the DOM: Navigation component

Mozilla · Firefox

8.8HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
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.
  • EPSS is 0.32% 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 Firefox 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.

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.

11 package states
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 · sourcefirefox-esrVendor fix publishedDebian records a fixed source-package version for this release.153.5.0esr-1~deb13u1Debian Security Tracker ↗Source updated 4 Nov 2026
Debian trixietrixie · sourcethunderbirdVendor fix publishedDebian records a fixed source-package version for this release.1:153.5.1esr-1~deb13u1Debian Security Tracker ↗Source updated 4 Nov 2026
Debian bookwormbookworm · sourcefirefox-esrVendor fix publishedDebian records a fixed source-package version for this release.153.5.0esr-1~deb12u1Debian Security Tracker ↗Source updated 4 Nov 2026
Debian bookwormbookworm · sourcethunderbirdVendor fix publishedDebian records a fixed source-package version for this release.1:153.5.1esr-1~deb12u1Debian Security Tracker ↗Source updated 4 Nov 2026
Debian forkyforky · sourcefirefox-esrVendor fix publishedDebian records a fixed source-package version for this release.153.5.0esr-1Debian Security Tracker ↗Source updated 4 Nov 2026
Debian forkyforky · sourcethunderbirdVendor fix publishedDebian records a fixed source-package version for this release.1:153.5.0esr-1Debian Security Tracker ↗Source updated 4 Nov 2026
Debian sidsid · sourcefirefoxVendor fix publishedDebian records a fixed source-package version for this release.158.0-1Debian Security Tracker ↗Source updated 4 Nov 2026
Debian sidsid · sourcefirefox-esrVendor fix publishedDebian records a fixed source-package version for this release.153.5.0esr-1Debian Security Tracker ↗Source updated 4 Nov 2026
Debian sidsid · sourcethunderbirdVendor fix publishedDebian records a fixed source-package version for this release.1:153.5.0esr-1Debian Security Tracker ↗Source updated 4 Nov 2026
Ubuntu 24.04 LTSnoble · standard archivemozjs102Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical Ubuntu Security ↗Source updated 4 Nov 2026
Ubuntu 24.04 LTSnoble · standard archivemozjs115Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical Ubuntu Security ↗Source updated 4 Nov 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-2026-109756 · CSAF 2.0 · revision 3 · finalRed Hat Product Securityfirefox: Privilege escalation in the DOM: Navigation component
18 known affected

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

  • firefox as a component of Red Hat Enterprise Linux 10
  • firefox.src as a component of Red Hat Enterprise Linux 10
  • rhel10/firefox-flatpak as a component of Red Hat Enterprise Linux 10
  • 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
  • firefox as a component of Red Hat Enterprise Linux 6
  • firefox.src as a component of Red Hat Enterprise Linux 6
  • thunderbird as a component of Red Hat Enterprise Linux 6
  • thunderbird.src as a component of Red Hat Enterprise Linux 6
  • firefox as a component of Red Hat Enterprise Linux 7
  • firefox.src as a component of Red Hat Enterprise Linux 7
Summary
A flaw was found in Firefox. The Mozilla Foundation's Security Advisory describes the following issue: Privilege escalation in the DOM: Navigation component
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
CVE-2026-109756 · CSAF 2.0 · revision 5 · interimSUSE Product Security TeamCVE-2026-109756
165 known affected

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

  • MozillaFirefox as component of SUSE Linux Enterprise Desktop 15 SP7
  • MozillaFirefox-devel as component of SUSE Linux Enterprise Desktop 15 SP7
  • MozillaFirefox-translations-common as component of SUSE Linux Enterprise Desktop 15 SP7
  • MozillaFirefox-translations-other as component of SUSE Linux Enterprise Desktop 15 SP7
  • MozillaThunderbird as component of SUSE Linux Enterprise Desktop 15 SP7
  • MozillaThunderbird-translations-common as component of SUSE Linux Enterprise Desktop 15 SP7
  • MozillaThunderbird-translations-other as component of SUSE Linux Enterprise Desktop 15 SP7
  • 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
Summary
Privilege escalation in the DOM: Navigation component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
Remediation
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
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-2026-98517

No EUVD known-exploited evidence

Privilege escalation in the DOM: Navigation component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

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
8.8 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

Privilege escalation in the DOM: Navigation component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

What

Privilege escalation in the DOM: Navigation component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

Why

The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.

How

An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may gain additional privileges.

What

Privilege escalation in the DOM: Navigation component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

Why

The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.

How

An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may gain additional privileges.

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 → Improper Privilege Management → gain additional privileges
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
Required interaction required
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-269 ↗

CWE-269: Improper Privilege Management. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.

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:R/S:U/C:H/I:H/A:H

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.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
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.
NetworkUnauthenticatedPrivilege escalationCWE-269
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-98517Official EUVD mapping

Privilege escalation in the DOM: Navigation component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

Official EUVD record ↗
BSI · German · WID-SEC-2026-3942Mozilla Firefox und Thunderbrid: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Mozilla Firefox und Mozilla Thunderbrid ausnutzen, um seine Privilegien zu erhöhen, Sicherheitsmaßnahmen zu umgehen, Spoofing-Angriffe durchzuführen, Daten offenzulegen oder zu manipulieren, Denial-of-Service-Zustände zu verursachen oder andere, nicht näher spezifizierte Angriffe durchzuführen.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-1305Avis du CERT-FR

747 Référence CVE CVE-2026-109748 https://www.cve.org/CVERecord?id=CVE-2026-109748 Référence CVE CVE-2026-109749 https://www.cve.org/CVERecord?id=CVE-2026-109749 Référence CVE CVE-2026-109750 https://www.cve.org/CVERecord?id=CVE-2026-109750 Référence CVE CVE-2026-109751 https://www.cve.org/CVERecord?id=CVE-2026-109751 Référence CVE CVE-2026-109752 https://www.cve.org/CVERecord?id=CVE-2026-109752 Référence CVE CVE-2026-109753 https://www.cve.org/CVERecord?id=CVE-2026-109753 Référence CVE CVE-2026-109754 https://www.cve.org/CVERecord?id=CVE-2026-109754 Référence CVE CVE-2026-109755 https://www.cve.org/CVERecord?id=CVE-2026-109755 Référence CVE CVE-2026-109756 https://www.cve.org/CVERecord?id=CVE-2026-109756 Référence CVE CVE-2026-109757 https://www.cve.org/CVERecord?id=CVE-2026-109757 Référence CVE CVE-2026-109759 https://www.cve.org/CVERecord?id=CVE-2026-109759 Référence CVE CVE-2026-109760 https://www.cve.org/CVERecord?id=CVE-2026-109760 Référence CVE CVE-2026-109761 https://www.cve.org/CVERecord?id=CVE-2026-109761 Référence CVE CVE-2026-109762 https://www.cve.org/CVERecord?id=CVE-2026-109762 Référence CVE CVE-2026-109763 https://www.cve.org/CVERecord?id=CVE-2026-109763 Référence CVE CVE-2026-109764 https://www.cve.org/CVERecord?id=CVE-2026-109764 Référence CVE CVE-2026-109765 https://www.cve.o

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.
Patch available
Affected
Fixed
Action
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
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 articles4 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 Firefox 158 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 29 Oct 2026Security Vulnerabilities fixed in Firefox 158 Announced October 13, 2026 Impact high Products Firefox Fixed in Firefox 158 Note : We have changed how we publish advisories. We no longer roll all internally identified memory safety vulnerabilities into a single CVE and are now issuing an advisory for every indivi
  • Security Vulnerabilities fixed in Firefox ESR 153.5 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 29 Oct 2026Security Vulnerabilities fixed in Firefox ESR 153.5 Announced October 13, 2026 Impact high Products Firefox ESR Fixed in Firefox ESR 153.5 Note : We have changed how we publish advisories. We no longer roll all internally identified memory safety vulnerabilities into a single CVE and are now issuing an advisory
  • Security Vulnerabilities fixed in Thunderbird 158 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 29 Oct 2026Security Vulnerabilities fixed in Thunderbird 158 Announced October 13, 2026 Impact high Products Thunderbird Fixed in Thunderbird 158 Many of these flaws cannot be exploited through email in the Thunderbird product because scripting is disabled when reading mail, however they may pose risks in browser or browse
  • Security Vulnerabilities fixed in Thunderbird 153.5 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 29 Oct 2026Security Vulnerabilities fixed in Thunderbird 153.5 Announced October 13, 2026 Impact high Products Thunderbird Fixed in Thunderbird 153.5 Many of these flaws cannot be exploited through email in the Thunderbird product because scripting is disabled when reading mail, however they may pose risks in browser or br
04

Evidence and provenance

Published 13 Oct 2026 · Last source change 14 Oct 2026, 03:59 UTC · CWE-269 · Improper Privilege Management

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 2026-10-14
European sourceENISA EUVD · EUVD-2026-98517
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCISA ADP
NVD statusNVD not scheduled

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
    firefox as a component of Red Hat Enterprise Linux 10; firefox.src as a component of Red Hat Enterprise Linux 10; rhel10/firefox-flatpak as a component of Red Hat Enterprise Linux 10; 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; firefox as a component of Red Hat Enterprise Linux 6; firefox.src as a component of Red Hat Enterprise Linux 6; thunderbird as a component of Red Hat Enterprise Linux 6; thunderbird.src as a component of Red Hat Enterprise Linux 6; firefox as a component of Red Hat Enterprise Linux 7; firefox.src as a component of Red Hat Enterprise Linux 7; thunderbird as a component of Red Hat Enterprise Linux 7; thunderbird.src as a component of Red Hat Enterprise Linux 7; firefox as a component of Red Hat Enterprise Linux 8; firefox.src as a component of Red Hat Enterprise Linux 8; 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 · Fixed: firefox-0:153.5.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-0:153.5.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-0:153.5.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-0:153.5.0-1.el9_8.src as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-0:153.5.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-debuginfo-0:153.5.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-debuginfo-0:153.5.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-debuginfo-0:153.5.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-debuginfo-0:153.5.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-debugsource-0:153.5.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-debugsource-0:153.5.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-debugsource-0:153.5.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-debugsource-0:153.5.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-x11-0:153.5.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-x11-0:153.5.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-x11-0:153.5.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-x11-0:153.5.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
    After
    firefox as a component of Red Hat Enterprise Linux 10; firefox.src as a component of Red Hat Enterprise Linux 10; rhel10/firefox-flatpak as a component of Red Hat Enterprise Linux 10; 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; firefox as a component of Red Hat Enterprise Linux 6; firefox.src as a component of Red Hat Enterprise Linux 6; thunderbird as a component of Red Hat Enterprise Linux 6; thunderbird.src as a component of Red Hat Enterprise Linux 6; firefox as a component of Red Hat Enterprise Linux 7; firefox.src as a component of Red Hat Enterprise Linux 7; thunderbird as a component of Red Hat Enterprise Linux 7; thunderbird.src as a component of Red Hat Enterprise Linux 7; firefox as a component of Red Hat Enterprise Linux 8; firefox.src as a component of Red Hat Enterprise Linux 8; thunderbird as a component of Red Hat Enterprise Linux 8; thunderbird.src as a component of Red Hat Enterprise Linux 8 · Fixed: firefox-0:153.5.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-0:153.5.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-0:153.5.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-0:153.5.0-1.el9_8.src as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-0:153.5.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-debuginfo-0:153.5.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-debuginfo-0:153.5.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-debuginfo-0:153.5.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-debuginfo-0:153.5.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-debugsource-0:153.5.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-debugsource-0:153.5.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-debugsource-0:153.5.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-debugsource-0:153.5.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-x11-0:153.5.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-x11-0:153.5.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-x11-0:153.5.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); firefox-x11-0:153.5.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:153.5.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:153.5.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:153.5.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:153.5.0-1.el9_8.src as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-0:153.5.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:153.5.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:153.5.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:153.5.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debuginfo-0:153.5.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:153.5.0-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:153.5.0-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:153.5.0-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9); thunderbird-debugsource-0:153.5.0-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
    Red Hat Product Security ↗
  2. ENISA EUVD mappingEUVD-2026-98517 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-98517"}
    ENISA EUVD ↗
  3. Vendor guidanceAuthoritative vendor guidance changed: added remediation: bugzilla.mozilla.org/show_bug.cgi?id=2069258; removed remediation: mozilla.org/mfsa2026-109.
    Before
    remediation: mozilla.org/mfsa2026-109
    After
    remediation: bugzilla.mozilla.org/show_bug.cgi?id=2069258
    CNA ↗
  4. Vendor guidanceAuthoritative vendor guidance changed: added remediation: mozilla.org/mfsa2026-109; removed remediation: bugzilla.mozilla.org/show_bug.cgi?id=2069258.
    Before
    remediation: bugzilla.mozilla.org/show_bug.cgi?id=2069258
    After
    remediation: mozilla.org/mfsa2026-109
    CNA ↗
  5. Affected versionsThe structured affected or fixed version information changed.
    Before
    See the vendor and CVE records for the affected range. · Fixed: Firefox: 153.5 ≤ 153.*, 158 ≤ *
    After
    See the vendor and CVE records for the affected range. · Fixed: Firefox: 153.5 ≤ 153.*, 158 ≤ *; Thunderbird: 153.5 ≤ 153.*, 158 ≤ *
    CNA ↗
  6. SeveritySeverity changed from Unknown to High.
    Before
    Unknown
    After
    High
    CISA ADP ↗
  7. CVSS scoreCVSS score changed from not recorded to 8.8 (CVSS 3.1 · CISA ADP · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).
    Before
    not recorded
    After
    8.8 (CVSS 3.1 · CISA ADP · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H)
    CISA ADP ↗
  8. 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-2026-98517↗Vendor CSAF · Red Hat Product Security↗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-2026-109756 · cve.blacktree.nl