Type Confusion in Microsoft SharePoint Server - CVE-2026-109499
Published: November 10, 2026
Vulnerability identifier: #VU164750
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-109499
CWE-ID: CWE-843
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to execute arbitrary code on the affected SharePoint server.
The vulnerability exists due to type confusion in Microsoft SharePoint Server when processing specially crafted content submitted over the network. A remote user can submit such content to a SharePoint site on which they have the Design permission to execute arbitrary code on the affected server.
Affected software
Microsoft SharePoint Server
How to mitigate CVE-2026-109499
Install security update from vendor's website.
Microsoft SharePoint Server - update to 16.0.20326.20278