CVE-2026-56164 Microsoft SharePoint Server Missing Authentication for Critical Function
An unauthorized attacker can elevate privileges over the network due to missing authentication for a critical function in Microsoft SharePoint Server.
- Exploited in the wild
- Since 14 Jul 2026
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-56164?
CVE-2026-56164 is a medium-severity missing authorization vulnerability in Microsoft Sharepoint Server, published on 14 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Missing authentication for critical function in Microsoft Office SharePoint allows an unauthorized attacker to elevate privileges over a network.
Weakness: CWE-306
Which versions are affected by CVE-2026-56164?
It affects 1 product.
Products include Microsoft Sharepoint Server.
How do I fix CVE-2026-56164?
No fix has been published for CVE-2026-56164 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 17 Jul 2026.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-56164 being exploited?
Yes. Attackers have exploited CVE-2026-56164 in the wild since at least 14 Jul 2026.
Public exploit code: 2 proofs of concept on GitHub.
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-hc2f-r46j-4w6x.