MSRXCVE-2026-55040
CVE-2026-55040
Microsoft SharePoint Server Security Feature Bypass Vulnerability
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
CVSS 3.1 · CNA
chance of exploitation in the next 30 days (EPSS; in the top 1% of all CVEs)
Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.
Affected products
- Microsoft Microsoft SharePoint Enterprise Server 2016: 16.0.0 to < 16.0.5561.1001
- Microsoft Microsoft SharePoint Server 2019: 16.0.0 to < 16.0.10417.20175
- Microsoft Microsoft SharePoint Server Subscription Edition: 16.0.0 to < 16.0.19725.20434
Weakness: CWE-1390
1 references (advisories, patches, write-ups)
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55040 · vendor-advisory, patch
Sources: CVE.org, FIRST EPSS. Missing ones did not answer or have no record yet.