Microsoft SharePoint Deserialization of Untrusted Data Vulnerability (CVE-2026-20963)
Severity: critical · Patch status: unknown · Since 2026-03-18 · CVE-2026-20963
Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network. CISA added CVE-2026-20963 to its Known Exploited Vulnerabilities catalog on Mar 18, 2026, which means attackers are exploiting it in the wild.
What to do
- Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- US federal agencies must remediate by Mar 21, 2026 (BOD 22-01); treat that as the outer limit.
Sources
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