[ CVE-2026-20963 · Published 13 Jan 2026 ]
Microsoft SharePoint Deserialization of Untrusted Data Vulnerability
Exploited · CISA KEV CVSS 9.8
EPSS 29%No fix listed yet
[ Why it matters ]Priority signals
- Exploited in the wild: on CISA's Known Exploited Vulnerabilities list since 2026-03-18
- EPSS: 29% chance of exploitation in the next 30 days (higher than 98% of CVEs)
- Critical severity: CVSS 9.8
[ Description ]Official description
Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
CISA: Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.
[ Fixes ]Fixes and patches
CISA required action (US federal deadline 21 Mar 2026): Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.
[ References ]References
- msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20963Vendor Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalogUS Government Resource