Firefox Same-origin policy bypass in JAR component before 148/ESR 140.8
CVE-2026-2790 Published on February 24, 2026
Same-origin policy bypass in the Networking: JAR component
Same-origin policy bypass in the Networking: JAR component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
Vulnerability Analysis
CVE-2026-2790 is exploitable with network access, requires 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 very high.
Weakness Type
Origin Validation Error
The software does not properly verify that the source of data or communication is valid.
Products Associated with CVE-2026-2790
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Affected Versions
Mozilla Firefox:- 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.