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.
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)
| Vendor | Product | Versions |
|---|---|---|
| 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
- Microsoft SharePoint Server Elevation of Privilege Vulnerability vendor-advisory, patch
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-56164 government-resource