Privilege Escalation in Firefox MessagingSystem <148 (ESR <115.33,140.8)
CVE-2026-2777 Published on February 24, 2026
Privilege escalation in the Messaging System component
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.
Vulnerability Analysis
CVE-2026-2777 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to be critical as this vulnerability has a high impact to the confidentiality, integrity and availability of this component.
Weakness Type
Improper Privilege Management
The software does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.
Products Associated with CVE-2026-2777
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Affected Versions
Mozilla Firefox:- Version 115.33, <= 115.* is unaffected.
- Version 140.8, <= 140.* is unaffected.
- Version 148, <= * is unaffected.
- Version 140.8, <= 140.* is unaffected.
- Version 148, <= * is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.