CVE-2021-26855🔥 Known Exploited (CISA KEV)CRITICAL9.1CVSS Severity ScoreEPSS Score77.9900%EPSS Percentile90.51thPublished2021-03-03Last Modified2025-12-18Data SourcesNVDCISA KEVFIRST.org EPSSVulnerability DescriptionMicrosoft Exchange Server Remote Code Execution VulnerabilityAffected Platforms (CPE)📦MicrosoftExchange Server= 2013= 2016= 2019References & Advisories🔗 http://packetstormsecurity.com/files/161846/Microsoft-Exchange-2019-SSRF-Arbitrary-File-Write.html🔗 http://packetstormsecurity.com/files/161938/Microsoft-Exchange-ProxyLogon-Remote-Code-Execution.html🔗 http://packetstormsecurity.com/files/162610/Microsoft-Exchange-2019-Unauthenticated-Email-Download.html🔗 http://packetstormsecurity.com/files/162736/Microsoft-Exchange-ProxyLogon-Collector.html🔗 https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26855🔗 http://packetstormsecurity.com/files/161846/Microsoft-Exchange-2019-SSRF-Arbitrary-File-Write.html🔗 http://packetstormsecurity.com/files/161938/Microsoft-Exchange-ProxyLogon-Remote-Code-Execution.html🔗 http://packetstormsecurity.com/files/162610/Microsoft-Exchange-2019-Unauthenticated-Email-Download.html