CVE-2026-56164: Microsoft SharePoint Server Missing Authentication for Critical Function Vulnerability
Summary
A critical vulnerability (CVE-2026-56164) exists in Microsoft SharePoint Server that allows unauthorized network attackers to escalate privileges. CISA is mandating that federal agencies apply mitigations by July 17, 2026, adhering to risk-based patching guidance and forensic triage requirements.
IFF Assessment
This vulnerability allows privilege escalation, which is a significant threat to an organization's security posture.
Severity
The CVSS score of 9.8 reflects the high impact of this vulnerability, allowing privilege escalation over a network with low complexity.
CISA KEV: Listed as actively exploited. Federal patch due: July 17, 2026. Known ransomware use: Unknown.
Defender Context
Defenders need to prioritize patching or mitigating this critical vulnerability in Microsoft SharePoint Server environments. The privilege escalation capability makes it a high-value target for attackers seeking to gain deeper access within a network. It is crucial to follow CISA's guidance on risk-based patching and forensic readiness.