All vulnerabilities
CVE-2026-20963

Microsoft SharePoint Deserialization of Untrusted Data Vulnerability

Microsoft SharePointApplications & CMS
Open in ThreatlineRecord JSON
CVSS
9.8Critical
ExploitationExploited in the wildAdded to KEV 18 Mar 2026CISA KEV
Exploit odds (EPSS)29.2%Chance of exploitation activity in the next 30 days, higher than 98% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in16.0.5535.1001Also 16.0.10417.20083, 16.0.19127.20442CVE List
Federal deadline21 Mar 2026Remediation due date for US federal agenciesCISA KEV
CISA required actionApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. CISA KEV

What fixes it

  • 16.0.5535.1001Microsoft SharePoint Enterprise Server 2016CVE List
  • 16.0.10417.20083Microsoft SharePoint Server 2019CVE List
  • 16.0.19127.20442Microsoft SharePoint Server Subscription EditionCVE List

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Timeline

  1. 13 Jan 2026, 17:56 UTCPublishedCVE List
  2. 18 Mar 2026Added to CISA KEVCISA KEV

Description

Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.

Text from CVE List

Affected versions 3

  • Microsoft SharePoint Enterprise Server 2016affected: 16.0.0 before 16.0.5535.1001CVE List
  • Microsoft SharePoint Server 2019affected: 16.0.0 before 16.0.10417.20083CVE List
  • Microsoft SharePoint Server Subscription Editionaffected: 16.0.0 before 16.0.19127.20442CVE List

References 3