CVE-2026-2776

10.0 criticalEPSS 0.6%

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

Severity

CVSS 3.1

10.0 critical

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

EPSS: 0.6% chance of exploitation in the next 30 days; higher than 46% of CVEs (scores of 2026-10-31)
CWE: CWE-119
Published: 2026-02-24
Modified: 2026-07-15
Record from: the NVD, synced 2026-10-19

Affected

mozilla:firefox
mozilla:thunderbird

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2015266
https://www.mozilla.org/security/advisories/mfsa2026-13/
https://www.mozilla.org/security/advisories/mfsa2026-14/
https://www.mozilla.org/security/advisories/mfsa2026-15/
https://www.mozilla.org/security/advisories/mfsa2026-16/

Check your stack JSON