CVE-2025-9866: Medium Inappropriate implementation in Extensions.
Chromium: CVE-2025-9866 Inappropriate implementation in Extensions
Other sources
Inappropriate implementation in Extensions in Google Chrome prior to 140.0.7339.80 allowed a remote attacker to bypass content security policy via a crafted HTML page. (Chromium security severity: Medium)
— MITRE
This CVE was assigned by Chrome. Microsoft Edge (Chromium-based) ingests Chromium, which addresses this vulnerability. Please see Google Chrome Releases for more information.
— Microsoft
Credit
Affected Software
Event History
Peer vulnerabilities
Found alongside the following vulnerabilities.
Frequently Asked Questions
What is the severity of CVE-2025-9866?
The severity of CVE-2025-9866 is classified as Medium.
How do I fix CVE-2025-9866?
To fix CVE-2025-9866, update Google Chrome to version 140.0.7339.80 or later.
What does CVE-2025-9866 allow an attacker to do?
CVE-2025-9866 allows a remote attacker to bypass the content security policy via a crafted HTML page.
Which versions of Google Chrome are affected by CVE-2025-9866?
Google Chrome versions prior to 140.0.7339.80 are affected by CVE-2025-9866.
Who is responsible for the vulnerability identified as CVE-2025-9866?
CVE-2025-9866 is associated with an inappropriate implementation in the Extensions of Google Chrome.