9.1
Critical
CVE-2025-6427 An attacker was able to bypass the `connect-src` directive of a Content Security Policy by manipulating subdocuments
Description
An attacker was able to bypass the `connect-src` directive of a Content Security Policy by manipulating subdocuments. This would have also hidden the connections from the Network tab in Devtools. This vulnerability was fixed in Firefox 140 and Thunderbird 140.
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Firefox 140 | earliest → < 140 | 140 |
| Thunderbird 140 | earliest → < 140 | 140 |
References
- bugzilla.mozilla.org bugzilla.mozilla.org
- www.mozilla.org www.mozilla.org
- www.mozilla.org www.mozilla.org
Timeline
- Published
- Last modified
Other CVEs of Firefox
The 2221 CVEs of Firefox →
CVE-2026-120572
Incorrect boundary conditions in the Layout: Block and Inline component
8.8
High
CVE-2026-118027
Frame poisoning in the Layout component
9.1
Critical
CVE-2026-118024
Use-after-free in the Graphics: Text component
8.8
High
CVE-2026-118026
Invalid pointer in the JavaScript: GC component
8.8
High