CVE-2021-34473
9.1CRITICALMicrosoft Exchange Server Remote Code Execution Vulnerability
Published: 7/14/2021Updated: 10/29/2025
CISA Known Exploited Vulnerability
Microsoft Exchange Server contains an unspecified vulnerability that allows for remote code execution.
Required Action:
Apply updates per vendor instructions.
Due Date:
2021-11-17
Known Ransomware Use
Description
Microsoft Exchange Server Remote Code Execution Vulnerability
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Affected Products
microsoftexchange_server
2013
microsoftexchange_server
2016
microsoftexchange_server
2016
microsoftexchange_server
2019
microsoftexchange_server
2019
References
- http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.htmlExploitThird Party AdvisoryVDB Entry
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34473PatchVendor Advisory
- https://www.zerodayinitiative.com/advisories/ZDI-21-821/Third Party AdvisoryVDB Entry
- http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.htmlExploitThird Party AdvisoryVDB Entry
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34473PatchVendor Advisory
- https://www.zerodayinitiative.com/advisories/ZDI-21-821/Third Party AdvisoryVDB Entry
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-34473US Government Resource