Use-after-free in the XML component of Mozilla Firefox
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- Low · Low · Low
- Fix status
- Partial Red Hat: 5 without a fix
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat.
Summary
Mozilla Firefox and Thunderbird contain a use-after-free flaw in the XML component, classified as CWE-416. A remote attacker without privileges can trigger it if a user interacts with attacker-controlled content, which can partially expose data and affect integrity and availability.
Written with Claude Haiku 5.5 from the sources below · 2026-11-04
Description from the CNA
Use-after-free in the XML 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
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Mozilla | Firefox | — | 115.44, 153.6, 159 | Patch available | CNA |
| Mozilla | Thunderbird | — | 153.6, 159 | Patch available | CNA |
Remediation
Upgrade Firefox to 115.44 ESR, 153.6 ESR or 159, and Thunderbird to 153.6 or 159. The sources list no fixed version for Red Hat Enterprise Linux 7, 8, 9 and 10, and no fix planned for Red Hat Enterprise Linux 6.
Written with Claude Haiku 5.5 from the sources below · 2026-11-04
- 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 →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet |
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
Timeline
- 2026-10-27 Threatist record created from CVE-2026-117880
- 2026-10-27 Fix available: Mozilla/Thunderbird@159 · CNA
- 2026-10-27 1 new reference · CNA
- 2026-10-27 Fix available: Mozilla/[email protected] · CNA
- 2026-10-27 1 new reference · CNA
- 2026-10-27 Alias added: GHSA-9h46-mqg4-pxfj
- 2026-10-29 Affected versions changed · Red Hat
- 2026-10-29 CVSS score added · Red Hat
- 2026-11-04 CVSS score added · CISA ADP
- 2026-11-04 Weakness changed · CISA ADP
- 2026-11-04 CISA SSVC decision points changed
References
Other 6
- https://bugzilla.mozilla.org/show_bug.cgi?id=2075996
- https://www.mozilla.org/security/advisories/mfsa2026-118/
- https://www.mozilla.org/security/advisories/mfsa2026-119/
- https://www.mozilla.org/security/advisories/mfsa2026-120/
- https://www.mozilla.org/security/advisories/mfsa2026-121/
- https://www.mozilla.org/security/advisories/mfsa2026-122/
More Mozilla vulnerabilities
- 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
Sources
- CVE-2026-117880 · CVE Program
- CVE-2026-117880 · NVD
- FIRST EPSS
- GHSA-9h46-mqg4-pxfj · GitHub Advisory Database · CC BY 4.0
- CVE-2026-117880 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences