Microsoft SharePoint Server Deserialization of Untrusted Data Vulnerability

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• NewsExploited · CISA KEVKnown ransomware useMicrosoft · SharePoint Server

  Microsoft SharePoint Server Deserialization of Untrusted Data Vulnerability

  CVE-2026-45659

  Microsoft SharePoint Server contains a deserialization of untrusted data vulnerability which allows an authorized attacker to execute code over a network.

  CISA's required action · due 4 Jul 2026 for U.S. federal civilian agencies

  Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

  Cited by CISA: msrc.microsoft.com · nvd.nist.gov

  Added to KEV 1 Jul 2026 · Source checked 4 Nov 2026, 16:30 UTC · CISA KEV entry

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