critical Known exploitedREV. 01

CVE-2026-56164Microsoft SharePoint Server — unauthenticated privilege escalation

A critical function in Microsoft SharePoint Server is reachable without signing in at all, so an attacker who can talk to the site over the network can raise themselves to privileged access on the server.

YOUR NEXT MOVE

Patch SharePoint Server with the Microsoft update now; if it is internet-facing, assume reach and hunt for new web parts, timer jobs and accounts.

Read the risk

THE VITAL STATS
CVSS score
9.8/ 10
CVSS v3.1
EPSS probability
27%
Likelihood of exploitation
Attack complexity
Low
Conditions needed to exploit
Known exploited
Yes — CISA KEV
CVE published
2026-07-14
Added to KEV
2026-07-14
Exploit published
Not recorded
Confidence
high
Kill chain
initial access
MITRE ATT&CK
T1190
Severity
critical

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attacker needsNetwork access to the SharePoint server; no account needed.

Behind the card

3 REFERENCES
Field-level provenanceTRACE THE SOURCES +

Which source supports each field, when it was retrieved, and who extracted it.

FieldsSourceRetrievedExtractorConfidence
cvss, exploitation.attack_complexity, exploitation.exploit_available, references, published_atnvd.nist.gov2026-09-23scrty-crds-pipeline/0.1high
exploitation.known_exploited, exploitation.kev_addedcisa.gov2026-09-23scrty-crds-pipeline/0.1high
epssapi.first.org2026-09-23scrty-crds-pipeline/0.1high
title, summary, severity, remediation, mitre_attack, kill_chain, recommended_action, confidence, tags, exploitation.prerequisitesnvd.nist.gov2026-09-23claude-codehigh

Printing history

THE RECORD
  1. r1Initial base card

First printing. This card has not been reprinted since publication.

crds:cve-2026-56164 · CRDS 0.1 · Issued 2026-09-23