critical Known exploitedREV. 01

CVE-2026-58644Microsoft SharePoint — deserialization RCE (CVE-2026-58644)

Microsoft SharePoint unpacks attacker-supplied serialized data without checking it, so an unauthenticated attacker on the network can run code on the server. Exploited in the wild.

YOUR NEXT MOVE

Apply Microsoft's SharePoint update for CVE-2026-58644 now; limit internet exposure of SharePoint until patched and triage servers for compromise per CISA guidance.

Read the risk

THE VITAL STATS
CVSS score
9.8/ 10
CVSS v3.1
EPSS probability
61%
Likelihood of exploitation
Attack complexity
Low
Conditions needed to exploit
Known exploited
Yes — CISA KEV
CVE published
2026-07-14
Added to KEV
2026-07-16
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 a vulnerable SharePoint server; no account or user interaction 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.gov2026-09-22scrty-crds-pipeline/0.1high
exploitation.known_exploited, exploitation.kev_addedcisa.gov2026-09-22scrty-crds-pipeline/0.1high
epssapi.first.org2026-09-22scrty-crds-pipeline/0.1high
title, summary, severity, remediation, mitre_attack, kill_chain, recommended_action, confidence, tags, exploitation.prerequisitesnvd.nist.gov2026-09-22claude-codehigh

Printing history

THE RECORD
  1. r1Initial base card

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

crds:cve-2026-58644 · CRDS 0.1 · Issued 2026-09-22