What is CVE-2026-55040?

CVE-2026-55040 is a security advisory published by Microsoft Security Response Center (MSRC) with Critical severity. Microsoft SharePoint Server Security Feature Bypass Vulnerability

Which CVE IDs does CVE-2026-55040 cover?

CVE-2026-55040 covers the following CVE IDs: CVE-2026-55040. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

What is the CVSS v3 score of CVE-2026-55040?

CVE-2026-55040 has a CVSS v3 base score of 9.1, published by Microsoft Security Response Center (MSRC).

Which products are affected by CVE-2026-55040?

CVE-2026-55040 affects 3 products, including: Microsoft SharePoint Enterprise Server 2016; Microsoft SharePoint Server 2019; Microsoft SharePoint Server Subscription Edition.

CVE-2026-55040CriticalCVSS 9.1

Microsoft SharePoint Server Security Feature Bypass Vulnerability

Vendor

Microsoft Security Response Center (MSRC)

Published

July 17, 2026

Last Modified

—

🔗 CVE IDs covered (1)

CVE-2026-55040 →

📋 Description

Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.

🎯 Affected products3

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

✅ Remediation

KB5002891 (Security Update) — fixed build 16.0.5561.1001 KB5002883 (Security Update) — fixed build 16.0.10417.20175 KB5002882 (Security Update) — fixed build 16.0.19725.20434

🔗 References (7)

advisoryhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55040
patchhttps://www.microsoft.com/en-us/download/details.aspx?id=108723
referencehttps://support.microsoft.com/help/5002891
patchhttps://www.microsoft.com/en-us/download/details.aspx?id=108726
referencehttps://support.microsoft.com/help/5002883
patchhttps://www.microsoft.com/en-us/download/details.aspx?id=108730
referencehttps://support.microsoft.com/help/5002882