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TI-2026-71668 Aliases CVE-2026-109745GHSA-fhx5-x7g9-94qv

Sandbox escape due to uninitialized memory in the DOM: Web Serial component

Priority MEDIUM 43CWE-908Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 4 fixed, 4 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 flaw in the DOM Web Serial component. Use of uninitialized memory (CWE-908) lets attacker-controlled content escape the browser sandbox. A remote attacker needs a user to interact with that content for the attack to work.

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

Description from the CNA

Sandbox escape due to uninitialized memory in the DOM: Web Serial component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00349 28th percentileScored 2026-11-07
Fix Partial Firefox (Mozilla): 153.5, 158Thunderbird (Mozilla): 153.5, 158Red Hat: 5 advisoriesRed Hat: 4 fixed, 4 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—153.5, 158Patch availableCNA
MozillaThunderbird—153.5, 158Patch availableCNA
  • Firefox VendorMozilla Affected — Fixed in 153.5, 158 Patch available CNA
  • Thunderbird VendorMozilla Affected — Fixed in 153.5, 158 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 and Thunderbird to version 153.5 or 158. Red Hat fixes Firefox in RHSA-2026:89756 (RHEL AppStream version 8) and RHSA-2026:89757 (RHEL AppStream version 9), and Thunderbird in RHSA-2026:93443 (RHEL AppStream version 9), RHSA-2026:95596 (RHEL AppStream EUS version 9.6) and RHSA-2026:95597 (RHEL AppStream E4S version 9.4). Red Hat lists RHEL 6 with no fix planned, and RHEL 7, RHEL 8 and RHEL 10 with no fix available.

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

  • Fix · CNA Firefox (Mozilla) Fixed in 153.5, 158
  • Fix · CNA Thunderbird (Mozilla) Fixed in 153.5, 158

Red Hat 5 advisories

  • RHSA-2026:95596 Released 2026-11-05 · Red Hat rating Important
    thunderbird security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) thunderbird-153.5.0-1.el9_6
  • RHSA-2026:95597 Released 2026-11-05 · Red Hat rating Important
    thunderbird security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream E4S (v.9.4) thunderbird-153.5.0-1.el9_4
  • RHSA-2026:93443 Released 2026-11-02 · Red Hat rating Important
    thunderbird security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 9) thunderbird-153.5.0-1.el9_8
Show 2 more Red Hat advisories
  • RHSA-2026:89757 Released 2026-10-26 · Red Hat rating Important
    firefox security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 9) firefox-153.5.0-1.el9_8, firefox-x11-153.5.0-1.el9_8
  • RHSA-2026:89756 Released 2026-10-26 · Red Hat rating Important
    firefox security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 8) firefox-153.5.0-1.el8_10

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 AppStream (v. 8)Fixed RHSA-2026:89756
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:89757, RHSA-2026:93443
Red Hat Enterprise Linux AppStream E4S (v.9.4)Fixed RHSA-2026:95597
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:95596

Timeline

  1. 2026-10-13 Threatist record created from CVE-2026-109745
  2. 2026-10-13 Alias added: GHSA-fhx5-x7g9-94qv
  3. 2026-10-13 Fix available: Mozilla/[email protected], Mozilla/Thunderbird@158 · CNA
  4. 2026-10-13 2 new references · CNA
  5. 2026-10-19 CVSS score added · CISA ADP
  6. 2026-10-19 Weakness changed · CISA ADP
  7. 2026-10-19 CISA SSVC decision points changed
  8. 2026-10-19 Priority changed: LOW → MEDIUM
  9. 2026-10-31 Affected versions changed · Red Hat
  10. 2026-10-31 CVSS score added · Red Hat
  11. 2026-10-31 Fix available: RHSA-2026:89757 · Red Hat
  12. 2026-10-31 Fix available: RHSA-2026:89756 · Red Hat
  13. 2026-10-31 Fix available: Red Hat Enterprise Linux AppStream (v. 8), Red Hat Enterprise Linux AppStream (v. 9) · Red Hat
  14. 2026-11-02 Fix available: RHSA-2026:93443 · Red Hat
  15. 2026-11-02 Affected versions changed · Red Hat
  16. 2026-11-06 Fix available: RHSA-2026:95597 · Red Hat
  17. 2026-11-06 Fix available: Red Hat Enterprise Linux AppStream E4S (v.9.4), Red Hat Enterprise Linux AppStream EUS (v.9.6) · Red Hat
  18. 2026-11-06 Fix available: RHSA-2026:95596 · 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