CVE-2026-65801 Microsoft Exchange Online Elevation of Privilege Vulnerability

Critical 10.0 Published 20 Aug 2026 Updated 28 Oct 2026

An unauthorized attacker can exploit a server-side request forgery flaw in Microsoft Exchange Online to elevate privileges over the network.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-65801?

CVE-2026-65801 is a critical server-side request forgery vulnerability in Microsoft Exchange Online, published on 20 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Server-side request forgery (ssrf) in Microsoft Exchange Online allows an unauthorized attacker to elevate privileges over a network.

Weakness: CWE-918

Which versions are affected by CVE-2026-65801?

It affects 1 product.

Products include Microsoft Exchange Online.

How do I fix CVE-2026-65801?

No fix has been published for CVE-2026-65801 yet. Limit exposure of the affected software until one is available.

Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.

Is CVE-2026-65801 being exploited?

There is no known exploitation of CVE-2026-65801 in the wild and no public exploit code.

Sources

Also known as GHSA-w5cc-jcwc-q4f8.