What is CVE-2026-70306?

CVE-2026-70306 is a critical-severity vulnerability in Microsoft Sharepoint Enterprise Server 2016, classified under Cross-site Scripting. CVSS score: 9.3/10. Published 2026-08-11.

How severe is CVE-2026-70306?

Critical severity. CVSS v3 base score is 9.3 out of 10.

XSS in Microsoft Sharepoint Enterprise Server 2016

CVE-2026-70306

Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an unauthorized attacker to perform spoofing over a network.

Vulnerability class: XSS (Cross-Site Scripting)

CVSS v3 metric

CVSS v3 base score 9.3 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N.

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-79 — Cross-site Scripting

References

secure@microsoft.com (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-70306?: CVE-2026-70306 is a critical-severity vulnerability in Microsoft Sharepoint Enterprise Server 2016, classified under Cross-site Scripting. CVSS score: 9.3/10. Published 2026-08-11.
How severe is CVE-2026-70306?: Critical severity. CVSS v3 base score is 9.3 out of 10.