Vulnerabilities & Exploits · Web App Attack

Critical SharePoint Flaw Being Actively Exploited

A critical remote-code-execution flaw in Microsoft SharePoint (CVE-2026-20963) is being exploited in the wild. Microsoft released fixes in January 2026 for SharePoint Server 2016, 2019, and Subscription Edition.

3 sources · Mar 19

CVE-2026-20963

NVD KEV

Known exploited · CISA KEV

CVSS 8.8 HIGH: deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a… EPSS 33% (98th percentile).

CISA federal remediation date Mar 21

Timeline

Sources

Vendor digest: Microsoft

Part of the PlainSec briefing for 2026-03-23

Every edition of this story: Critical SharePoint Flaw Being Actively Exploited

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