What is CVE-2026-64921?

CVE-2026-64921 is a high-severity vulnerability in Microsoft Sharepoint Enterprise Server 2016, classified under Missing Authentication for Critical Function. CVSS score: 8.8/10. Published 2026-08-11.

How severe is CVE-2026-64921?

High severity. CVSS v3 base score is 8.8 out of 10.

Auth bypass in Microsoft Sharepoint Enterprise Server 2016

CVE-2026-64921

Missing authentication for critical function in Microsoft Office SharePoint allows an authorized attacker to elevate privileges over a network.

Vulnerability class: Broken Authentication

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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

Weakness classification (CWE)

CWE-306 — Missing Authentication for Critical Function

References

Microsoft SharePoint Server Elevation of Privilege Vulnerability (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-64921?: CVE-2026-64921 is a high-severity vulnerability in Microsoft Sharepoint Enterprise Server 2016, classified under Missing Authentication for Critical Function. CVSS score: 8.8/10. Published 2026-08-11.
How severe is CVE-2026-64921?: High severity. CVSS v3 base score is 8.8 out of 10.