CVE-2025-6427

CRITICAL EPSS 21.8%
Published Jun 24, 20251y ago · Modified Jun 17, 20261w ago
9.1 CVSS 3.1
Critical
Find Similar
Published Jun 24, 2025 1y ago
Last Modified Jun 17, 2026 1w ago

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.

CVSS Details

Base Score
9.1
Exploitability
3.9
Impact
5.2
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability None

Threat Intelligence

EPSS Exploit Probability
21.8% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

CWE-693

Affected Products 1

VendorProductVersionRange
mozillafirefox* <140.0

References 3

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

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.