Known exploited vulnerability · Microsoft

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

criticalCVSS 3.1 9.8Exploited

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

Published Jan 13, 2026 · Updated Jun 17, 2026

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.

Advisory details

From the National Vulnerability Database. This product uses the NVD API but is not endorsed or certified by the NVD.

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

References

How this page is made: the data panel comes from the GitHub Advisory Database, CISA’s KEV catalog, the NVD and FIRST EPSS, and updates twice a day. No analysis has been written for this entry yet. Methodology

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