CVE-2026-2776

critical

Description

Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software. This vulnerability affects Firefox < 148, Firefox ESR < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.

References

https://www.mozilla.org/security/advisories/mfsa2026-17/

https://www.mozilla.org/security/advisories/mfsa2026-16/

https://www.mozilla.org/security/advisories/mfsa2026-15/

https://www.mozilla.org/security/advisories/mfsa2026-14/

https://www.mozilla.org/security/advisories/mfsa2026-13/

https://bugzilla.mozilla.org/show_bug.cgi?id=2015266

Details

Source: Mitre, NVD

Published: 2026-02-24

Updated: 2026-02-28

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: 10

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