Microsoft — Microsoft SharePoint Server Missing Authentication for Critical Function Vulnerability
CISA KEV · in the CISA KEV catalog since 2026-07-14
Listed in the CISA KEV catalog, and an EPSS probability of 0.010.
Patch This Cycle
The priority band answers “how soon”, not “how bad” — see Methodology for what it weighs and where it abstains.
| Measure | Value | Source | What it means |
|---|---|---|---|
| CVSS base score | 9.8 | NVD | How severe the flaw is in itself. It does not say how likely an attack is. |
| FIRST EPSS | 0.010 (62.5th pctl) | FIRST | FIRST's estimate of the chance this is exploited in the next 30 days, and how that ranks against all CVEs. |
| Actively exploited | Confirmed | CISA KEV | Whether a source of record has confirmed attacks using it in the wild. |
| Ransomware campaign use | Unknown or none | CISA KEV | Whether CISA has seen ransomware operators use it. |
| CISA remediation deadline | 2026-07-17 — CISA federal deadline · Overdue by 3 months | CISA KEV | The date US federal agencies must have fixed or mitigated it. |
| Fixed in | sharepoint server: update to 16.0.19725.20434 or later | NVD | The version(s) the vendor has published as fixed, where NVD records one. |
| Public exploit module | None known | Metasploit | Module existing is not the same as active exploitation. |
| EUVD cross-reference | Listed | ENISA EUVD | ENISA's own vulnerability database entry for this CVE, where one exists. |
Impacted software or hardware
Fixed versions: sharepoint server: update to 16.0.19725.20434 or later
Remediation: 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.
Remediation basis: CISA KEV required action
ENISA EUVD also lists this CVE at CVSS 5.3 (v3.1), assigned by microsoft. Source: euvd.enisa.europa.eu.
This page is an opinion about urgency. Where it and a source of record disagree, the source of record is the record.
Where this sits
CVE-2026-56164 is a Microsoft entry in the CISA KEV catalog. The priority feed ranks Microsoft's current monthly release rather than older Microsoft CVEs, so this one is not listed there; the page above scores it from the same sources.
