CVE-2026-57977 Microsoft Edge (Chromium-based) Spoofing Vulnerability

High 7.1 Published 3 Jul 2026 Updated 28 Oct 2026

An attacker can perform spoofing attacks via cross-site scripting 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-2026-57977?

CVE-2026-57977 is a high-severity cross-site scripting vulnerability in Microsoft Edge Chromium, published on 3 Jul 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

Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Edge (Chromium-based) allows an unauthorized attacker to perform spoofing over a network.

Weakness: CWE-79

Which versions are affected by CVE-2026-57977?

It affects 1 product.

Products include Microsoft Edge Chromium.

How do I fix CVE-2026-57977?

No fix has been published for CVE-2026-57977 yet. Limit exposure of the affected software until one is available.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2026-57977 being exploited?

There is no known exploitation of CVE-2026-57977 in the wild and no public exploit code.

All Microsoft Edge Chromium vulnerabilities

Sources

Also known as GHSA-4w42-h73x-mj6m.