Missing Authorization in Microsoft SharePoint Server - CVE-2026-88198
Published: October 14, 2026
Vulnerability identifier: #VU155389
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-2026-88198
CWE-ID: CWE-862
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to escalate privileges and overwrite arbitrary file content in the security context of the local system.
The vulnerability exists due to missing authorization in Microsoft Office SharePoint when handling requests for operations beyond the permissions granted to a user's account. A remote user can send a specially crafted request to an affected SharePoint server to escalate privileges and overwrite arbitrary file content in the security context of the local system.
No additional user interaction is required. The Preview Pane is not an attack vector.
Affected software
Microsoft SharePoint Server
How to mitigate CVE-2026-88198
Install security update from vendor's website.
Microsoft SharePoint Server - update to 16.0.20326.20190