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TI-2026-81323 Aliases CVE-2026-117997GHSA-55fm-xj42-jvx7

Use-after-free in Firefox Widget component enables sandbox escape

Priority MEDIUM 43CWE-416Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 5 without a fix

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.

Summary

Mozilla Firefox and Thunderbird contain a use-after-free in the Widget component (CWE-416), where memory is used after it has been freed. A remote attacker with no privileges can escape the browser sandbox if a user interacts with crafted content.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

Sandbox escape due to use-after-free in the Widget component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0038 32nd percentileScored 2026-11-07
Fix Partial Firefox (Mozilla): 153.6, 159Thunderbird (Mozilla): 153.6, 159Red Hat: 5 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
MozillaFirefox—153.6, 159Patch availableCNA
MozillaThunderbird—153.6, 159Patch availableCNA
  • Firefox VendorMozilla Affected — Fixed in 153.6, 159 Patch available CNA
  • Thunderbird VendorMozilla Affected — Fixed in 153.6, 159 Patch available CNA

CPE names Threatist (inferred) · 2

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*——Mozilla
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*——Mozilla
  • cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions — — ·Mozilla
  • cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions — — ·Mozilla

Remediation

Update Firefox to 159 or Firefox ESR to 153.6, and Thunderbird to 159 or 153.6. Red Hat Enterprise Linux 6, 7, 8, 9 and 10 are listed as affected without a fix: Red Hat Enterprise Linux 6 has no fix planned, and Red Hat Enterprise Linux 7, 8, 9 and 10 have none available.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA Firefox (Mozilla) Fixed in 153.6, 159
  • Fix · CNA Thunderbird (Mozilla) Fixed in 153.6, 159

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix yet
Red Hat Enterprise Linux 8AffectedNo fix yet
Red Hat Enterprise Linux 9AffectedNo fix yet

Timeline

  1. 2026-10-27 Threatist record created from CVE-2026-117997
  2. 2026-10-27 Fix available: Mozilla/Thunderbird@159 · CNA
  3. 2026-10-27 1 new reference · CNA
  4. 2026-10-27 Fix available: Mozilla/[email protected] · CNA
  5. 2026-10-27 1 new reference · CNA
  6. 2026-10-27 Alias added: GHSA-55fm-xj42-jvx7
  7. 2026-10-29 Affected versions changed · Red Hat
  8. 2026-10-29 CVSS score added · Red Hat
  9. 2026-10-30 Affected versions changed · Red Hat
  10. 2026-10-30 CVSS score changed · Red Hat
  11. 2026-11-02 Affected versions changed · Red Hat
  12. 2026-11-02 Affected versions changed · Red Hat
  13. 2026-11-05 CVSS score added · CISA ADP
  14. 2026-11-05 Weakness changed · CISA ADP
  15. 2026-11-05 CISA SSVC decision points changed
  16. 2026-11-05 Priority changed: LOW → MEDIUM
  17. 2026-11-05 Affected versions changed · Red Hat
  18. 2026-11-06 Affected versions changed · Red Hat

References

Other 5

  • TI-2024-08981 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.8
  • TI-2022-09832 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.6
  • TI-2019-08769 Improper input validation in Mozilla Firefox ESR KEVCVSS 3.1CRITICAL 10.0
  • TI-2010-03577 Mozilla Firefox 3.5.x through 3.5.14 and 3.6.x through 3.6.11, Thunderbird 3.1.6 before… KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-04799 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
  • TI-2023-04477 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
See all 4204 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences