Microsoft SharePoint Server Missing Authentication for Critical Function Vulnerability

What it is

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

Who's affected

Affects anyone running Microsoft SharePoint Server. Microsoft products in a small practice typically sit close to credentials, email, or document workflows — treat the patch as in-scope.

What to do

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.

If you don't have someone in-house to verify the patch deployed across every endpoint — or you're not sure whether you're affected — that's exactly the kind of triage we do. Book a free 20-minute triage call.

CISA due date

Federal deadline: July 17, 2026. Federal agencies must complete the required action by this date. For private SMBs the deadline is advisory — but treat it as a strong recommendation, especially if you handle regulated data (HIPAA, GLBA, ABA model rules).

EPSS

EPSS score: 5.6% — higher than 92% of all scored CVEs.

EPSS estimates the probability of exploitation activity in the next 30 days. Every entry on this site is already confirmed exploited, so read it as relative urgency among the things you still have open, not as permission to wait.

Score dated 2026-07-16, from the FIRST.org Exploit Prediction Scoring System.

Other exploited Microsoft SharePoint Server entries

More CISA KEV entries for Microsoft SharePoint Server. Same product line, same actively-exploited status.

• CVE-2026-45659: Microsoft SharePoint Server Deserialization of Untrusted Data Vulnerability
• CVE-2026-32201: Microsoft SharePoint Server Improper Input Validation Vulnerability
• CVE-2023-24955: Microsoft SharePoint Server Code Injection Vulnerability
• CVE-2023-29357: Microsoft SharePoint Server Privilege Escalation Vulnerability

Browse more

• All Microsoft KEV entries
• All SMB-relevant KEV entries

Source

This entry comes from CISA's Known Exploited Vulnerabilities catalog, public US-Government data we pull daily. The plain-language framing and the what-to-do guidance above are ours. View the original entry on cisa.gov.