CVE-2026-109705

CVSS 9.6 (critical) · published 2026-10-13

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.

Weakness: CWE-416

Source: NVD CVE-2026-109705

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=2040905
• https://www.mozilla.org/security/advisories/mfsa2026-106/
• https://www.mozilla.org/security/advisories/mfsa2026-108/
• https://www.mozilla.org/security/advisories/mfsa2026-109/
• https://www.mozilla.org/security/advisories/mfsa2026-110/
• https://www.mozilla.org/security/advisories/mfsa2026-119/

Check your software

Connect an AI agent to the Fixlane MCP server or ask the Telegram bot to check what you have installed against incidents with a verified fixed version.