Privilege escalation via undisclosed Netmonitor operation
Published Feb 24, 2026 · Updated Feb 24, 2026
Privilege escalation in Mozilla Netmonitor allows attackers to gain higher privileges in Firefox and Thunderbird release and ESR channels. Mozilla has not publicly disclosed the faulty Netmonitor operation, the input that reaches it, or the privilege boundary it crosses. CISA assesses network reachability without authentication and required user interaction; affected versions are Firefox before 148, Firefox ESR before 140.8, Thunderbird before 148, and Thunderbird ESR before 140.8.
Summary
What happened
Privilege escalation in Mozilla Netmonitor allows attackers to gain higher privileges in Firefox and Thunderbird release and ESR channels. Mozilla has not publicly disclosed the faulty Netmonitor operation, the input that reaches it, or the privilege boundary it crosses. CISA assesses network reachability without authentication and required user interaction; affected versions are Firefox before 148, Firefox ESR before 140.8, Thunderbird before 148, and Thunderbird ESR before 140.8.
The record
- CVE
- CVE-2026-2780
- Published
- Feb 24, 2026
- Updated
- Feb 24, 2026
- Vendor
- Mozilla
- Product
- Firefox
- Classifications
- CWE-269, T1068
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 24, 2026CVE publishedPublication date reported by the CVE source.
- Feb 24, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=unspecified <148
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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