Same-origin Policy Bypass in Firefox Networking:Cookies (before FF 152)
CVE-2026-12304 Published on June 16, 2026
Same-origin policy bypass in the Networking: Cookies component
Same-origin policy bypass in the Networking: Cookies component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.
Vulnerability Analysis
CVE-2026-12304 is exploitable 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 have a high impact on confidentiality and integrity, and no impact on availability.
Weakness Type
Origin Validation Error
The software does not properly verify that the source of data or communication is valid.
Products Associated with CVE-2026-12304
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Affected Versions
Mozilla Firefox:- Version 140.12, <= 140.* is unaffected.
- Version 152, <= * is unaffected.
- Version 140.12, <= 140.* is unaffected.
- Version 152, <= * 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.