CVE-2026-20963

Microsoft SharePoint Enterprise Server 2016, Microsoft SharePoint Server 2019, Microsoft SharePoint Server Subscription Edition

Published 13 Jan 2026 · updated 17 Jun 2026 · Analyzed

9.8 Critical · CVSS 3.1, microsoft.com

Exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on 18 Mar 2026, with a remediation deadline of 21 Mar 2026 for US federal agencies.

Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Description

Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20963 · Vendor Advisory
www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20963 · US Government Resource