Cache mitigation bypass
Published Feb 24, 2026 · Updated Feb 24, 2026
Mitigation bypass in Firefox before 148, Firefox ESR before 140.8, and Thunderbird before 148 or 140.8 lets remote attackers bypass a cache defense. Mozilla has not published the affected cache function or the incorrect operation that permits the mitigation to be bypassed; the linked bug remains access-restricted. The public record does not identify the security property defeated or a demonstrated consequence, so the impact remains unspecified despite NVD's unauthenticated network assessment.
Summary
What happened
Mitigation bypass in Firefox before 148, Firefox ESR before 140.8, and Thunderbird before 148 or 140.8 lets remote attackers bypass a cache defense. Mozilla has not published the affected cache function or the incorrect operation that permits the mitigation to be bypassed; the linked bug remains access-restricted. The public record does not identify the security property defeated or a demonstrated consequence, so the impact remains unspecified despite NVD's unauthenticated network assessment.
The record
- CVE
- CVE-2026-2791
- Published
- Feb 24, 2026
- Updated
- Feb 24, 2026
- Vendor
- Mozilla
- Product
- Firefox
- Classifications
- CWE-288
- 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?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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