CVE-2025-6427

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.

CVSS v3 9.1 CRITICAL

9.1^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://bugzilla.mozilla.org/show_bug.cgi?id=1966927	Permissions Required
https://www.mozilla.org/security/advisories/mfsa2025-51/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-54/

Configurations

Configuration 1 (hide)

cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*

History

No history.

Information

Published : 2025-06-24 13:15

Updated : 2026-06-17 10:01

NVD link : CVE-2025-6427

Mitre link : CVE-2025-6427

CVE.ORG link : CVE-2025-6427

JSON object : View

Products Affected

mozilla

firefox

CWE

CWE-693

Protection Mechanism Failure

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