Privilege escalation in cookie handling
Published Aug 18, 2026 · Updated Aug 21, 2026
Privilege escalation in affected Mozilla Firefox and Thunderbird releases allows attackers to gain elevated privileges through cookie processing. The flaw is in Networking: Cookies, but Mozilla has not published the faulty cookie operation or the privilege boundary it crosses. Firefox before 154 and ESR before 140.14 or 153.1 are affected, as are Thunderbird before 154 and ESR before 140.14 or 153.1; disabled mail scripting blocks ordinary email exploitation.
Summary
What happened
Privilege escalation in affected Mozilla Firefox and Thunderbird releases allows attackers to gain elevated privileges through cookie processing. The flaw is in Networking: Cookies, but Mozilla has not published the faulty cookie operation or the privilege boundary it crosses. Firefox before 154 and ESR before 140.14 or 153.1 are affected, as are Thunderbird before 154 and ESR before 140.14 or 153.1; disabled mail scripting blocks ordinary email exploitation.
The record
- CVE
- CVE-2026-74953
- Published
- Aug 18, 2026
- Updated
- Aug 21, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- T1068
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Aug 18, 2026CVE publishedPublication date reported by the CVE source.
- Aug 21, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
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CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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