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TI-2026-81267 Aliases CVE-2026-117941GHSA-q6cq-5fq7-r29j

Use-after-free in Firefox and Thunderbird CSS Object Model

Priority MEDIUM 40CWE-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 Mozilla Thunderbird contain a use-after-free flaw in the DOM CSS Object Model component (CWE-416). A remote attacker without privileges can trigger it if a user interacts with attacker-controlled content, with high impact on confidentiality, integrity and availability.

Written with Claude Haiku 5.5 from the sources below · 2026-11-05

Description from the CNA

Use-after-free in the DOM: CSS Object Model component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00397 34th percentileScored 2026-11-07
Fix Partial Firefox (Mozilla): 115.44, 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—115.44, 153.6, 159Patch availableCNA
MozillaThunderbird—153.6, 159Patch availableCNA
  • Firefox VendorMozilla Affected — Fixed in 115.44, 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 115.44 (ESR), 153.6 (ESR) or 159, and Thunderbird to 153.6 or 159. Red Hat lists Red Hat Enterprise Linux 6 as affected with no fix planned, and Red Hat Enterprise Linux 7, 8, 9 and 10 as affected with the plan none available.

Written with Claude Haiku 5.5 from the sources below · 2026-11-05

  • Fix · CNA Firefox (Mozilla) Fixed in 115.44, 153.6, 159
  • Fix · CNA Thunderbird (Mozilla) Fixed in 153.6, 159

Vendor assessments

Red Hat

Red Hat rating: Important. 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-2026-117941
  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-q6cq-5fq7-r29j
  7. 2026-10-29 Affected versions changed · Red Hat
  8. 2026-10-29 CVSS score added · Red Hat
  9. 2026-11-05 CVSS score added · CISA ADP
  10. 2026-11-05 Weakness changed · CISA ADP
  11. 2026-11-05 CISA SSVC decision points changed
  12. 2026-11-07 Priority changed: LOW → MEDIUM

References

Other 6

  • 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