CVE-2026-64921 Microsoft SharePoint Server Elevation of Privilege Vulnerability
An authorized attacker can elevate privileges over the network due to missing authentication for a critical function in Microsoft SharePoint Server.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-64921?
CVE-2026-64921 is a high-severity missing authorization vulnerability in Microsoft Sharepoint Server, published on 11 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Missing authentication for critical function in Microsoft Office SharePoint allows an authorized attacker to elevate privileges over a network.
Weakness: CWE-306
Which versions are affected by CVE-2026-64921?
It affects 1 product.
Products include Microsoft Sharepoint Server.
How do I fix CVE-2026-64921?
No fix has been published for CVE-2026-64921 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-2026-64921 being exploited?
There is no known exploitation of CVE-2026-64921 in the wild and no public exploit code.
Other vulnerabilities in Microsoft Sharepoint Server
- CVE-2026-50522 Microsoft SharePoint Deserialization of Untrusted Data Vulnerability
- CVE-2026-58644 Microsoft SharePoint Deserialization of Untrusted Data
- CVE-2026-20963 Microsoft SharePoint Deserialization of Untrusted Data
- CVE-2025-53770 Microsoft SharePoint Deserialization of Untrusted Data
- CVE-2023-29357 Microsoft SharePoint Server Privilege Escalation
Sources
Also known as GHSA-92r3-28gr-fr7w.