CVE-2026-2777
CRITICAL severity · CVSS 9.8 · Improper privilege management
9.8CVSS CRITICAL
Summary
Privilege escalation in the Messaging System component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
Impact & exploitability
Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
Exploit probability (EPSS)0%
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products we track (1)
Recommendation
Apply the vendor fix promptly. Open any affected product above for its exact safe version.
Additional information
- NVD record
- https://www.mozilla.org/security/advisories/mfsa2026-13/Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-14/Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-15/Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-16/Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-17/Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=2015305