{"id":"CVE-2021-42321","aliases":[],"url":"https://o3.security/vulnerability/CVE-2021-42321","summary":"Microsoft Exchange Server Remote Code Execution Vulnerability","details":"Microsoft Exchange Server Remote Code Execution Vulnerability","published":"2021-11-10T01:19:50.047","modified":"2026-08-19T19:23:07.277","cvss":{"score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":{"score":0.91737,"percentile":0.99811,"asOf":"2026-09-05"},"cisaKev":null,"exploitsKnown":11,"affectedPackages":[],"fix":null,"references":[{"type":"FIX","url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-42321"},{"type":"EXPLOIT","url":"http://packetstormsecurity.com/files/166153/Microsoft-Exchange-Server-Remote-Code-Execution.html"},{"type":"EXPLOIT","url":"http://packetstormsecurity.com/files/168131/Microsoft-Exchange-Server-ChainedSerializationBinder-Remote-Code-Execution.html"},{"type":"FIX","url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42321"},{"type":"WEB","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-42321"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-08-19T19:23:07.277"}}