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CVE-2021-31207

Known Exploited (CISA KEV)MEDIUM

6.6

CVSS Severity Score

EPSS Score78.6660%

EPSS Percentile94.66th

PublishedMay 11, 2021

Last ModifiedOct 30, 2025

Vulnerability Description

Microsoft Exchange Server Security Feature Bypass Vulnerability

Affected Platforms (CPE)

📦

Microsoft

Exchange Server

= 2013

📦

Microsoft

Exchange Server

= 2016

📦

Microsoft

Exchange Server

= 2016

📦

Microsoft

Exchange Server

= 2019

📦

Microsoft

Exchange Server

= 2019

References & Advisories

🔗 http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html

🔗 https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31207

🔗 https://www.zerodayinitiative.com/advisories/ZDI-21-819/

🔗 http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html

🔗 https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31207

🔗 https://www.zerodayinitiative.com/advisories/ZDI-21-819/

🔗 https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31207

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