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 affects 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 unspecified and below 148 is affected.
- Version unspecified and below 115.33 is affected.
- Version unspecified and below 140.8 is affected.
- Version unspecified and below 148 is affected.
- Version unspecified and below 140.8 is affected.
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.