CSIRTS // UNIFIED SECURITY ADVISORY FEEDSYS ● ONLINE · POWERED BY INTELFUSIONS.COM

← Back to feed

CVE-2026-20963: Microsoft SharePoint Deserialization of Untrusted Data Vulnerability

criticalknown exploitedCVE-2026-20963
Actively exploited. At least one CVE in this advisory is listed in the CISA Known Exploited Vulnerabilities catalog — exploitation has been observed in the wild. Treat remediation as urgent.
Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.

CSIRTS triage

vendor: Microsoftproduct: SharePointUnsafe deserialization
What
Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.
Who is affected
Deployments of Microsoft SharePoint are affected.
Urgency
Remediation is urgent due to active exploitation and critical severity.
Action
Apply the latest security patch for Microsoft SharePoint.

AI-assisted analysis generated from the source advisory — verify against the original.

⚡ Watch SharePoint

Get an email when a new SharePoint advisory drops — max one per day, one-click unsubscribe.

Details

Source
CISA Known Exploited Vulnerabilities (US · database · site)
Severity
critical
Published
2026-03-18
Exploitation
Observed in the wild (CISA KEV)

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-20963

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Referenced CVEs

CVECSIRTS overviewExternal
CVE-2026-20963coverage & exploitation statusNVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

Recent advisories for Microsoft SharePoint Deserialization

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

More from CISA Known Exploited Vulnerabilities