{"id":"CVE-2021-34473","aliases":[],"url":"https://o3.security/vulnerability/CVE-2021-34473","summary":"Microsoft Exchange Server Remote Code Execution Vulnerability","details":"Microsoft Exchange Server Remote Code Execution Vulnerability","published":"2021-07-14T18:15:11.163","modified":"2026-08-10T19:58:52.800","cvss":{"score":9.1,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"},"epss":{"score":0.99999,"percentile":0.99997,"asOf":"2026-09-05"},"cisaKev":null,"exploitsKnown":17,"affectedPackages":[],"fix":null,"references":[{"type":"FIX","url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34473"},{"type":"EXPLOIT","url":"http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html"},{"type":"FIX","url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34473"},{"type":"ADVISORY","url":"https://www.zerodayinitiative.com/advisories/ZDI-21-821/"},{"type":"WEB","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-34473"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-08-10T19:58:52.800"}}