Actively exploited · Published Jul 14, 2026 · Assigned by microsoft

CVE-2026-56164Microsoft SharePoint Server Elevation of Privilege Vulnerability

Medium 5.3 Exploited

In plain English

A medium-severity missing authentication in Microsoft SharePoint Enterprise Server 2016 from Microsoft. Attackers are actively exploiting it in the wild (listed by CISA on July 14, 2026). The chance it is exploited in the next 30 days is estimated at 1.0% (higher than 63% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. 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.

Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)1.0%top 36.7% of all CVEs
Exploited in the wildYesCISA KEV since Jul 14, 2026
Attack tooling1Public PoC

CISA guidance

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.

Federal agencies must remediate by Jul 17, 2026.

Official description

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

Affected products (as reported)

VendorProductVersions
Microsoft Microsoft SharePoint Enterprise Server 2016 16.0.0 – before 16.0.5561.1001
Microsoft Microsoft SharePoint Server 2019 16.0.0 – before 16.0.10417.20175
Microsoft Microsoft SharePoint Server Subscription Edition 16.0.0 – before 16.0.19725.20434

Weakness: CWE-306 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:F/RL:O/RC:C

References