Microsoft Exchange Server Security Feature Bypass Vulnerability

MEDIUM 6.6EXPLOITED (CISA KEV)CVE-2021-31207 · Published 11/05/2021 · updated 17/06/2026

Microsoft Exchange Server Security Feature Bypass Vulnerability. Actively exploited: CISA added this vulnerability to its Known Exploited Vulnerabilities catalog on 03/11/2021. Patch affected systems as an emergency. It is known to be used in ransomware campaigns.

Package	Affected versions	Patched versions
exchange server microsoft	`= 2013= 2016= 2019`	No fix yet

Description

References

packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html · Exploit
portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31207 · Patch
zerodayinitiative.com/advisories/ZDI-21-819 · Third Party Advisory
cisa.gov/known-exploited-vulnerabilities-catalog · US Government Resource
CISA KEV · CVE-2021-31207

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