CVE-2026-2777

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2026-2777
Privilege escalation in the Messaging System component. This vulnerability affects Firefox < 148, Firefox ESR < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.

9.8 /10

CVSS v3 : CRITICAL

V3 Legend

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References
Link Resource
https://bugzilla.mozilla.org/show_bug.cgi?id=2015305 Issue Tracking Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-13/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-14/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-15/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-16/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-17/ Vendor Advisory
Configurations

Configuration 1 (hide)

OR cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*
History

25 Feb 2026, 19:43

Type Values Removed Values Added
CWE CWE-269

25 Feb 2026, 16:24

Type Values Removed Values Added
CWE NVD-CWE-noinfo
CPE cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 9.8
First Time Mozilla
Mozilla firefox
Mozilla thunderbird
References () https://bugzilla.mozilla.org/show_bug.cgi?id=2015305 - () https://bugzilla.mozilla.org/show_bug.cgi?id=2015305 - Issue Tracking, Permissions Required
References () https://www.mozilla.org/security/advisories/mfsa2026-13/ - () https://www.mozilla.org/security/advisories/mfsa2026-13/ - Vendor Advisory
References () https://www.mozilla.org/security/advisories/mfsa2026-14/ - () https://www.mozilla.org/security/advisories/mfsa2026-14/ - Vendor Advisory
References () https://www.mozilla.org/security/advisories/mfsa2026-15/ - () https://www.mozilla.org/security/advisories/mfsa2026-15/ - Vendor Advisory
References () https://www.mozilla.org/security/advisories/mfsa2026-16/ - () https://www.mozilla.org/security/advisories/mfsa2026-16/ - Vendor Advisory
References () https://www.mozilla.org/security/advisories/mfsa2026-17/ - () https://www.mozilla.org/security/advisories/mfsa2026-17/ - Vendor Advisory

24 Feb 2026, 18:29

Type Values Removed Values Added
References
  • () https://www.mozilla.org/security/advisories/mfsa2026-16/ -
  • () https://www.mozilla.org/security/advisories/mfsa2026-17/ -
Summary (en) Privilege escalation in the Messaging System component. This vulnerability affects Firefox < 148, Firefox ESR < 115.33, and Firefox ESR < 140.8. (en) Privilege escalation in the Messaging System component. This vulnerability affects Firefox < 148, Firefox ESR < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.

24 Feb 2026, 14:16

Type Values Removed Values Added
New CVE
Information

Published : 2026-02-24 14:16

Updated : 2026-02-25 19:43

NVD link : CVE-2026-2777

Mitre link : CVE-2026-2777

CVE.ORG link : CVE-2026-2777

JSON object : View

Products Affected

mozilla

  • thunderbird
  • firefox
CWE
NVD-CWE-noinfo CWE-269

Improper Privilege Management