CVE-2026-102866 Microsoft Office SharePoint Elevation of Privilege Vulnerability
An attacker can bypass cryptographic signature verification to elevate privileges in Microsoft SharePoint Server.
- 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-2026-102866?
CVE-2026-102866 is a high-severity vulnerability in Microsoft Sharepoint Server, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Improper verification of cryptographic signature in Microsoft Office SharePoint allows an unauthorized attacker to elevate privileges over a network.
Weakness: CWE-347
Which versions are affected by CVE-2026-102866?
It affects 1 product.
Products include Microsoft Sharepoint Server.
How do I fix CVE-2026-102866?
No fix has been published for CVE-2026-102866 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-102866 being exploited?
There is no known exploitation of CVE-2026-102866 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-4394-9r85-5r5g.