Applied Cybernetics Group
Threat intel → detection pipeline
Friday, September 18, 2026
Data as of 13:09 UTC

Microsoft SharePoint Server Missing Authentication for Critical Function Vulnerability

Added to KEV
2026-07-14
Federal due date
2026-07-17
Vendor
Microsoft
Product
SharePoint Server
EPSS
97.9th percentile (score 0.266, as of 2026-09-16)
NVD CVSS v3.1
5.3 (MEDIUM)
Ransomware use
Unknown
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2026-56164

CISA short description

Microsoft SharePoint contains a missing authentication for critical function vulnerability that allows an unauthorized attacker to elevate privileges over a network.

Required action

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.

NVD description

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

EPSS percentile is the FIRST.org exploit-probability ranking as of the date noted above; it moves daily. CVSS reflects NVD's analysis at time of publication.