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Full vulnerability report · 2026
CVE-2026-16356High confidence

Sandbox escape due to use-after-free in the Disability Access APIs component

Mozilla · Firefox

9.8CriticalCVSS 3.1
Recommended action
Within 72 hours

Critical technical impact with a remotely reachable, unauthenticated path; no CISA KEV confirmation is currently recorded.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityCriticalOperational priority:Critical, 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 0.39% 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 3 daysRemediation target: Within 90 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.140.13.0esr-1~deb13u1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian trixietrixie · sourcethunderbirdVendor fix publishedDebian records a fixed source-package version for this release.1:140.13.0esr-2~deb13u1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian bookwormbookworm · sourcefirefox-esrVendor fix publishedDebian records a fixed source-package version for this release.140.13.0esr-1~deb12u1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian bookwormbookworm · sourcethunderbirdVendor fix publishedDebian records a fixed source-package version for this release.1:140.13.0esr-2~deb12u1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian forkyforky · sourcefirefox-esrVendor fix publishedDebian records a fixed source-package version for this release.140.13.0esr-1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian forkyforky · sourcethunderbirdVendor fix publishedDebian records a fixed source-package version for this release.1:140.13.0esr-1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian sidsid · sourcefirefoxVendor fix publishedDebian records a fixed source-package version for this release.153.0-1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian sidsid · sourcefirefox-esrVendor fix publishedDebian records a fixed source-package version for this release.140.13.0esr-1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian sidsid · sourcethunderbirdVendor fix publishedDebian records a fixed source-package version for this release.1:140.13.0esr-1Debian Security Tracker ↗Source updated 5 Oct 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 5 Oct 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 5 Oct 2026
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-2026-46204

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

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
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 72 hours

Critical technical impact with a remotely reachable, unauthenticated path; no CISA KEV confirmation is currently recorded.

Patch available
01

What, why and how

Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox 153, Firefox ESR 115.38, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

What

Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox 153, Firefox ESR 115.38, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

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

Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox 153, Firefox ESR 115.38, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

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 → Use After Free → 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-416 ↗

CWE-416: Use After Free. The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

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: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.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.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.
NetworkUnauthenticatedCWE-416
A

Official authority intelligence

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

BSI · German · WID-SEC-2026-2458Mozilla Firefox und Thunderbird: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Mozilla Firefox und Mozilla Thunderbird ausnutzen, um beliebigen Code auszuführen, Sicherheitsmaßnahmen zu umgehen, vertrauliche Informationen offenzulegen, Berechtigungen zu erweitern, Sandbox-Escapes durchzuführen, Daten zu manipulieren, einen Denial-of-Service-Zustand auszulösen oder Speicherbeschädigungen zu verursachen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260722Security Bulletin 22 Jul 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 22 Jul 2026, published on 22 July 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0913Multiples vulnérabilités dans Mozilla Thunderbird

d?id=CVE-2026-15718 Référence CVE CVE-2026-15719 https://www.cve.org/CVERecord?id=CVE-2026-15719 Référence CVE CVE-2026-16349 https://www.cve.org/CVERecord?id=CVE-2026-16349 Référence CVE CVE-2026-16350 https://www.cve.org/CVERecord?id=CVE-2026-16350 Référence CVE CVE-2026-16351 https://www.cve.org/CVERecord?id=CVE-2026-16351 Référence CVE CVE-2026-16352 https://www.cve.org/CVERecord?id=CVE-2026-16352 Référence CVE CVE-2026-16353 https://www.cve.org/CVERecord?id=CVE-2026-16353 Référence CVE CVE-2026-16354 https://www.cve.org/CVERecord?id=CVE-2026-16354 Référence CVE CVE-2026-16355 https://www.cve.org/CVERecord?id=CVE-2026-16355 Référence CVE CVE-2026-16356 https://www.cve.org/CVERecord?id=CVE-2026-16356 Référence CVE CVE-2026-16357 https://www.cve.org/CVERecord?id=CVE-2026-16357 Référence CVE CVE-2026-16358 https://www.cve.org/CVERecord?id=CVE-2026-16358 Référence CVE CVE-2026-16359 https://www.cve.org/CVERecord?id=CVE-2026-16359 Référence CVE CVE-2026-16360 https://www.cve.org/CVERecord?id=CVE-2026-16360 Référence CVE CVE-2026-16361 https://www.cve.org/CVERecord?id=CVE-2026-16361 Référence CVE CVE-2026-16362 https://www.cve.org/CVERecord?id=CVE-2026-16362 Référence CVE CVE-2026-16363 https://www.cve.org/CVERecord?id=CVE-2026-16363 Référence CVE CVE-2026-16364 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0910Multiples vulnérabilités dans les produits Mozilla

d?id=CVE-2026-15718 Référence CVE CVE-2026-15719 https://www.cve.org/CVERecord?id=CVE-2026-15719 Référence CVE CVE-2026-16349 https://www.cve.org/CVERecord?id=CVE-2026-16349 Référence CVE CVE-2026-16350 https://www.cve.org/CVERecord?id=CVE-2026-16350 Référence CVE CVE-2026-16351 https://www.cve.org/CVERecord?id=CVE-2026-16351 Référence CVE CVE-2026-16352 https://www.cve.org/CVERecord?id=CVE-2026-16352 Référence CVE CVE-2026-16353 https://www.cve.org/CVERecord?id=CVE-2026-16353 Référence CVE CVE-2026-16354 https://www.cve.org/CVERecord?id=CVE-2026-16354 Référence CVE CVE-2026-16355 https://www.cve.org/CVERecord?id=CVE-2026-16355 Référence CVE CVE-2026-16356 https://www.cve.org/CVERecord?id=CVE-2026-16356 Référence CVE CVE-2026-16357 https://www.cve.org/CVERecord?id=CVE-2026-16357 Référence CVE CVE-2026-16358 https://www.cve.org/CVERecord?id=CVE-2026-16358 Référence CVE CVE-2026-16359 https://www.cve.org/CVERecord?id=CVE-2026-16359 Référence CVE CVE-2026-16360 https://www.cve.org/CVERecord?id=CVE-2026-16360 Référence CVE CVE-2026-16361 https://www.cve.org/CVERecord?id=CVE-2026-16361 Référence CVE CVE-2026-16362 https://www.cve.org/CVERecord?id=CVE-2026-16362 Référence CVE CVE-2026-16363 https://www.cve.org/CVERecord?id=CVE-2026-16363 Référence CVE CVE-2026-16364 https://www.cve.org/CVERecord?id=

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-025112Mozilla FoundationのMozilla Firefox等の複数製品における複数の脆弱性

障害者支援APIコンポーネントにおけるUse-After-Freeの脆弱性により、サンドボックスをエスケープされる問題が発生します。この脆弱性は、Firefox 153、Firefox ESR 115.38、Firefox ESR 140.13、Thunderbird 153、およびThunderbird 140.13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.
Patch available
Affected
See the vendor and CVE records for the affected range.
Fixed
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
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 articles10 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 140.13 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 28 Sep 2026Security Vulnerabilities fixed in Thunderbird 140.13 Announced July 21, 2026 Impact critical Products Thunderbird Fixed in Thunderbird 140.13 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 Firefox ESR 115.38 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 28 Sep 2026Security Vulnerabilities fixed in Firefox ESR 115.38 Announced July 21, 2026 Impact critical Products Firefox ESR Fixed in Firefox ESR 115.38 # CVE-2026-15719: Site isolation issue in the DOM: Navigation component Reporter Atsushi Sada Impact critical Description We are aware that exploit code for this is p
  • Security Vulnerabilities fixed in Firefox ESR 140.13 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 28 Sep 2026Security Vulnerabilities fixed in Firefox ESR 140.13 Announced July 21, 2026 Impact critical Products Firefox ESR Fixed in Firefox ESR 140.13 # CVE-2026-15718: Invalid pointer in the JavaScript: WebAssembly component Reporter Christian Holler Impact critical Description We are aware that exploit code for th
  • Security Vulnerabilities fixed in Firefox 153 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 27 Sep 2026Security Vulnerabilities fixed in Firefox 153 Announced July 21, 2026 Impact high Products Firefox Fixed in Firefox 153 # CVE-2026-16349: Same-origin policy bypass in the DOM: Navigation component Reporter Tran Quac Impact high References Bug 2034682 # CVE-2026-16350: Incorrect boundary conditions in the A
  • Security Vulnerabilities fixed in Thunderbird 153 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 27 Sep 2026Security Vulnerabilities fixed in Thunderbird 153 Announced July 21, 2026 Impact high Products Thunderbird Fixed in Thunderbird 153 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 browser
  • Security Vulnerabilities fixed in Thunderbird 153 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 27 Sep 2026Security Vulnerabilities fixed in Thunderbird 153 Announced July 21, 2026 Impact high Products Thunderbird Fixed in Thunderbird 153 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 browser
  • Security Vulnerabilities fixed in Thunderbird 140.13 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 27 Sep 2026Security Vulnerabilities fixed in Thunderbird 140.13 Announced July 21, 2026 Impact critical Products Thunderbird Fixed in Thunderbird 140.13 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 Firefox 153 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 27 Sep 2026Security Vulnerabilities fixed in Firefox 153 Announced July 21, 2026 Impact high Products Firefox Fixed in Firefox 153 # CVE-2026-16349: Same-origin policy bypass in the DOM: Navigation component Reporter Tran Quac Impact high References Bug 2034682 # CVE-2026-16350: Incorrect boundary conditions in the A
  • Security Vulnerabilities fixed in Firefox ESR 140.13 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 27 Sep 2026Security Vulnerabilities fixed in Firefox ESR 140.13 Announced July 21, 2026 Impact critical Products Firefox ESR Fixed in Firefox ESR 140.13 # CVE-2026-15718: Invalid pointer in the JavaScript: WebAssembly component Reporter Christian Holler Impact critical Description We are aware that exploit code for th
  • Security Vulnerabilities fixed in Firefox ESR 115.38 — Mozilla →Original publisher ↗Searchable text snapshot · Captured 27 Sep 2026Security Vulnerabilities fixed in Firefox ESR 115.38 Announced July 21, 2026 Impact critical Products Firefox ESR Fixed in Firefox ESR 115.38 # CVE-2026-15719: Site isolation issue in the DOM: Navigation component Reporter Atsushi Sada Impact critical Description We are aware that exploit code for this is p
04

Evidence and provenance

Published 21 Jul 2026 · Last source change 22 Jul 2026, 19:18 UTC · CWE-416 · Use After Free

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 2026-08-14
European sourceENISA EUVD · EUVD-2026-46204
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCISA ADP
NVD statusNVD enriched

Missing structured fields: affected versions. Missing data is not evidence of low risk; review the primary advisory.

Material change intelligence

What changed after publication

View recent updates ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

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-2026-46204↗Vendor advisory↗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-2026-16356 · cve.blacktree.nl