MSRC-CVE-2026-70306 — Microsoft Office SharePoint Spoofing Vulnerability

Summary

Impact: Spoofing. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.

Details

How could an attacker exploit this vulnerability?
An attacker could send a specially crafted URL to an authenticated SharePoint user and persuade them to visit it and submit the form. Successful exploitation could allow the attacker to run script in the user's SharePoint session, potentially accessing information or modifying site content.

Security updates
16.0.5565.1001 — https://support.microsoft.com/help/5002905
16.0.10417.20198 — https://support.microsoft.com/help/5002894
16.0.19725.20522 — https://support.microsoft.com/help/5002893

Vulnerabilities 1

Critical 9.3

CVE-2026-70306

Microsoft Office SharePoint Spoofing Vulnerability

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.

Microsoft Microsoft SharePoint Server 2019 Microsoft SharePoint Enterprise Server 2016 Microsoft SharePoint Server Subscription Edition

Aug 11, 2026

Revision history

2026-08-11 #1
Information published.

References

CVE-2026-70306 Microsoft Office SharePoint Spoofing Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70306
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
Common Vulnerability Scoring System
https://www.first.org/cvss