What’s Vulnerable › Vulnerabilities

CVE-2025-14331: Same-origin policy bypass in the Request Handling component

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-12-09 · updated 2026-10-07
• Weakness: CWE-346

Description

Same-origin policy bypass in the Request Handling component. This vulnerability was fixed in Firefox 146, Firefox ESR 115.31, Firefox ESR 140.6, Thunderbird 146, and Thunderbird 140.6.

Affected products

• Mozilla Firefox: before 115.31.0; before 146.0; from 116.0 before 140.6.0 — fixed in 115.31.0, 140.6.0, 146.0
• Mozilla Thunderbird: before 140.6.0; before 146.0 — fixed in 140.6.0, 146.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 115.31.0, 140.6.0, 146.0; Mozilla Thunderbird 140.6.0, 146.0. Check the vendor advisory for mitigations.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=2000218
• https://www.mozilla.org/security/advisories/mfsa2025-92/
• https://www.mozilla.org/security/advisories/mfsa2025-93/
• https://www.mozilla.org/security/advisories/mfsa2025-94/
• https://www.mozilla.org/security/advisories/mfsa2025-95/
• https://www.mozilla.org/security/advisories/mfsa2025-96/

Get alerted when CVE-2025-14331 or the next vulnerability affects your stack