What is CVE-2025-21393?

CVE-2025-21393 is a medium-severity vulnerability in Microsoft Sharepoint Enterprise Server 2016, classified under Cross-site Scripting. CVSS score: 6.3/10. Published 2025-01-14.

How severe is CVE-2025-21393?

Medium severity. CVSS v3 base score is 6.3 out of 10.

XSS in Microsoft Sharepoint Enterprise Server 2016

CVE-2025-21393

Microsoft SharePoint Server Spoofing Vulnerability

Vulnerability class: XSS (Cross-Site Scripting)

Published 2025-01-14 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:N.

EPSS exploit prediction

EPSS: 0.011 (63.7th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 64th percentile — 63.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000

Affected products

Microsoft Sharepoint Enterprise Server 2016 — versions 16.0.0
Microsoft Sharepoint Server 2019 — versions 16.0.0
Microsoft Sharepoint Server Subscription Edition — versions 16.0.0
Microsoft Sharepoint Server — versions 2016, 2019

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21393 (vendor-advisory, Patch, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2025-21393?: CVE-2025-21393 is a medium-severity vulnerability in Microsoft Sharepoint Enterprise Server 2016, classified under Cross-site Scripting. CVSS score: 6.3/10. Published 2025-01-14.
How severe is CVE-2025-21393?: Medium severity. CVSS v3 base score is 6.3 out of 10.