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CVE-2025-6427

Critical

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.

SeverityCritical
CVSS9.1
Exploit probability—
ProductMozilla Firefox
PublishedJun 24, 2025
First seenJun 24, 2025
Weakness typeCWE-693CWE-693

How to fix

Update
  • mozilla firefox140.0 or later

Affected products

ProductAffected versionsFixed in
mozilla firefoxv < 140.0140.0

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