CVE-2026-66798 Microsoft Edge (Chromium-based) Remote Code Execution Vulnerability

Medium 4.3 Published 28 Aug 2026 Updated 28 Oct 2026

An attacker can execute arbitrary code remotely via a use-after-free flaw in Microsoft Edge, requiring users to apply vendor patches.

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: None listed

What is CVE-2026-66798?

CVE-2026-66798 is a medium-severity use after free vulnerability in Microsoft Edge Chromium, published on 28 Aug 2026. 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

Use after free in Microsoft Edge (Chromium-based) allows an unauthorized attacker to execute code over a network.

Weakness: CWE-416

Which versions are affected by CVE-2026-66798?

It affects 1 product.

Products include Microsoft Edge Chromium.

How do I fix CVE-2026-66798?

No fix has been published for CVE-2026-66798 yet. Limit exposure of the affected software until one is available.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2026-66798 being exploited?

There is no known exploitation of CVE-2026-66798 in the wild and no public exploit code.

All Microsoft Edge Chromium vulnerabilities

Sources

Also known as GHSA-c27v-65fh-7pg2.