Cross-site scripting in Microsoft SharePoint Server - CVE-2026-55021
Published: July 17, 2026
Vulnerability identifier: #VU138271
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-55021
CWE-ID: CWE-79
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Microsoft
Affected software:
Microsoft SharePoint Server
Microsoft SharePoint Server
Detailed vulnerability description
The vulnerability allows a remote user to perform spoofing.
The vulnerability exists due to cross-site scripting in Microsoft Office SharePoint when generating web pages. A remote user can send a malicious link to a user and convince the user to open it to perform spoofing.
User interaction is required.
How to mitigate CVE-2026-55021
Install security update from vendor's website.