CVE-2025-6427
Mozilla Firefox Content Security Policy Bypass
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 affects Firefox < 140 and Thunderbird < 140.
INFO
Published Date :
June 24, 2025, 1:15 p.m.
Last Modified :
July 14, 2025, 7:15 p.m.
Source :
[email protected]
Remotely Exploitable :
Yes !
Impact Score :
5.2
Exploitability Score :
3.9
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-6427.
| URL | 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/ |
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-6427 vulnerability anywhere in the article.
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Cyber Security News
Firefox 140 Released With Fix for Code Execution Vulnerability – Update Now
Mozilla has released Firefox 140, addressing multiple critical security vulnerabilities, including a high-impact use-after-free vulnerability that could lead to code execution. The update patches twel ... Read more
The following table lists the changes that have been made to the
CVE-2025-6427 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by [email protected]
Jul. 14, 2025
Action Type Old Value New Value Changed 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 affects Firefox < 140. 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 affects Firefox < 140 and Thunderbird < 140. Added Reference https://www.mozilla.org/security/advisories/mfsa2025-54/ -
Initial Analysis by [email protected]
Jul. 03, 2025
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:* versions up to (excluding) 140.0 Added Reference Type Mozilla Corporation: https://bugzilla.mozilla.org/show_bug.cgi?id=1966927 Types: Permissions Required Added Reference Type Mozilla Corporation: https://www.mozilla.org/security/advisories/mfsa2025-51/ Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 25, 2025
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Added CWE CWE-693 -
New CVE Received by [email protected]
Jun. 24, 2025
Action Type Old Value New Value Added 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 affects Firefox < 140. Added Reference https://bugzilla.mozilla.org/show_bug.cgi?id=1966927 Added Reference https://www.mozilla.org/security/advisories/mfsa2025-51/
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-6427 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-6427
weaknesses.