CVE-2026-66311 Microsoft Edge (Chromium-based) Tampering Vulnerability
An unauthorized local attacker can tamper with Microsoft Edge data due to missing authorization checks.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-66311?
CVE-2026-66311 is a medium-severity missing authorization vulnerability in Microsoft Edge Chromium, published on 3 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Missing authorization in Microsoft Edge (Chromium-based) allows an unauthorized attacker to perform tampering locally.
Weakness: CWE-862
Which versions are affected by CVE-2026-66311?
It affects 1 product.
Products include Microsoft Edge Chromium.
How do I fix CVE-2026-66311?
No fix has been published for CVE-2026-66311 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-66311 being exploited?
There is no known exploitation of CVE-2026-66311 in the wild and no public exploit code.
Other vulnerabilities in Microsoft Edge Chromium
- CVE-2024-21326 Microsoft Edge (Chromium-based) Elevation of Privilege Vulnerability
- CVE-2023-35618 Microsoft Edge (Chromium-based) Elevation of Privilege Vulnerability
- CVE-2023-36735 Microsoft Edge (Chromium-based) Elevation of Privilege Vulnerability
- CVE-2022-33649 Microsoft Edge (Chromium-based) Security Feature Bypass Vulnerability
- CVE-2026-58289 Microsoft Edge (Chromium-based) Remote Code Execution Vulnerability
Sources
Also known as GHSA-78rr-mxgh-pv8f.