CVE-2025-9866 Security feature bypass in Chrome
Remote attackers can bypass Content Security Policy in Google Chrome via crafted HTML pages, requiring users to upgrade to the latest version.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2025-9866?
CVE-2025-9866 is a high-severity vulnerability in Google Chrome, published on 3 Sep 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
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)
Weakness: CWE-693
Which versions are affected by CVE-2025-9866?
It affects 1 product.
Products include Google Chrome.
How do I fix CVE-2025-9866?
Upgrade to a fixed version.
Is CVE-2025-9866 being exploited?
There is no known exploitation of CVE-2025-9866 in the wild and no public exploit code.
Other vulnerabilities in Google Chrome
Sources
Also known as DEBIAN-CVE-2025-9866, GHSA-5g75-w57p-pj3x.