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TI-2026-71854 Aliases CVE-2026-109705GHSA-mjw9-3pg2-vh5w

Sandbox escape and use-after-free in Mozilla Firefox and Thunderbird

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 fixed, 3 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 flaw in the Networking component (CWE-416). A remote attacker without privileges can trigger it when a user interacts with malicious content, and the impact extends beyond the vulnerable component. The same release also fixes a sandbox escape and a site isolation issue caused by incorrect boundary conditions.

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

Description from the CNA

Sandbox escape, site isolation issue due to incorrect boundary conditions, use-after-free in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, Thunderbird 153.5, and Firefox ESR 115.44.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00325 25th percentileScored 2026-11-07
Fix Partial Firefox (Mozilla): 115.44, 153.5, 158Thunderbird (Mozilla): 153.5, 158Red Hat: 6 advisoriesRed Hat: 5 fixed, 3 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, 153.5, 158Patch availableCNA
MozillaThunderbird—153.5, 158Patch availableCNA
  • Firefox VendorMozilla Affected — Fixed in 115.44, 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 to 115.44, 153.5 or 158 and Thunderbird to 153.5 or 158. Red Hat fixes Firefox in RHSA-2026:89756 (RHEL 8), RHSA-2026:89757 (RHEL 9) and RHSA-2026:89758 (RHEL 10), and Thunderbird in RHSA-2026:93443 (RHEL 9), RHSA-2026:95596 (EUS 9.6) and RHSA-2026:95597 (E4S 9.4). Red Hat lists Red Hat Enterprise Linux 7, 8 and 10 as affected without a fix plan.

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

  • Fix · CNA Firefox (Mozilla) Fixed in 115.44, 153.5, 158
  • Fix · CNA Thunderbird (Mozilla) Fixed in 153.5, 158

Red Hat 6 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 3 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
  • RHSA-2026:89758 Released 2026-10-26 · Red Hat rating Important
    firefox security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 10) firefox-153.5.0-1.el10_2

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 7AffectedNo fix yet
Red Hat Enterprise Linux 8AffectedNo fix yet
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:89758
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
Not affected: 3 products
  • Red Hat Enterprise Linux 10
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7

Timeline

  1. 2026-10-13 Threatist record created from CVE-2026-109705
  2. 2026-10-13 Alias added: GHSA-mjw9-3pg2-vh5w
  3. 2026-10-13 Fix available: Mozilla/[email protected], Mozilla/Thunderbird@158 · CNA
  4. 2026-10-13 2 new references · CNA
  5. 2026-10-23 Affected versions changed · Red Hat
  6. 2026-10-23 CVSS score added · Red Hat
  7. 2026-10-27 Fix available: Mozilla/[email protected] · CNA
  8. 2026-10-27 1 new reference · CNA
  9. 2026-10-30 Affected versions changed · Red Hat
  10. 2026-10-31 Fix available: RHSA-2026:89758 · 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. 10), 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. 2026-11-05 Fix available: Red Hat Enterprise Linux AppStream E4S (v.9.4) · Red Hat
  17. 2026-11-06 Fix available: Red Hat Enterprise Linux AppStream EUS (v.9.6) · Red Hat
  18. 2026-11-06 Fix available: RHSA-2026:95597 · Red Hat
  19. 2026-11-06 Fix available: RHSA-2026:95596 · Red Hat

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