Known Exploited Vulnerability: CVE-2026-42897

Vendor: Microsoft

Product: Microsoft

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.

Known ransomware campaign use: Unknown

Notes: https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-42897 https://learn.microsoft.com/en-us/exchange/plan-and-deploy/post-installation-tasks/security-best-practices/exchange-emergency-mitigation-service https://nvd.nist.gov/vuln/detail/CVE-2026-42897

CWEs