[ CVE-2021-42321 · Published 10 Nov 2021 ]
Microsoft Exchange Server Remote Code Execution Vulnerability
Exploited · CISA KEV CVSS 8.8
EPSS 92%Fix available
[ Why it matters ]Priority signals
- Exploited in the wild: on CISA's Known Exploited Vulnerabilities list since 2021-11-17
- Known to be used in ransomware campaigns
- EPSS: 92% chance of exploitation in the next 30 days (higher than 100% of CVEs)
[ Description ]Official description
Microsoft Exchange Server Remote Code Execution Vulnerability
CISA: An authenticated attacker could leverage improper validation in cmdlet arguments within Microsoft Exchange and perform remote code execution.
[ Fixes ]Fixes and patches
CISA required action (US federal deadline 1 Dec 2021): Apply updates per vendor instructions.
- Patch on msrc.microsoft.comVendor patch or bulletin · NVD · Reference tagged 'Patch' by NVD
- Patch on portal.msrc.microsoft.comVendor patch or bulletin · NVD · Reference tagged 'Patch' by NVD
[ References ]References
- msrc.microsoft.com/update-guide/vulnerability/CVE-2021-42321PatchVendor Advisory
- packetstormsecurity.com/files/166153/Microsoft-Exchange-Server-Remote-Code-Execution.htmlExploitThird Party AdvisoryVDB Entry
- packetstormsecurity.com/files/168131/Microsoft-Exchange-Server-ChainedSerializationBind…ExploitThird Party AdvisoryVDB Entry
- portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42321PatchVendor Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalogUS Government Resource