CVE-2026-109705

critical

Description

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, and Thunderbird 153.5.

References

https://www.mozilla.org/security/advisories/mfsa2026-110/

https://www.mozilla.org/security/advisories/mfsa2026-109/

https://www.mozilla.org/security/advisories/mfsa2026-108/

https://www.mozilla.org/security/advisories/mfsa2026-106/

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-98483

https://bugzilla.mozilla.org/show_bug.cgi?id=2040905

Details

Source: Mitre, NVD

Published: 2026-10-13

Updated: 2026-10-13

Risk Information

CVSS v2

Base Score: 10

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

Severity: Critical

CVSS v3

Base Score: 9.6

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H