{"id":"CVE-2021-31209","aliases":["EUVD-2021-18122","GHSA-v623-3qmp-8rrh"],"status":"published","title":"Microsoft Exchange Server Spoofing Vulnerability","description":"Microsoft Exchange Server Spoofing Vulnerability","severity":{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N/E:U/RL:O/RC:C","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.02627,"percentile":0.85626,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-290"],"published":"2021-05-11T19:11:43Z","modified":"2026-06-17T03:51:27Z","products":[{"vendor":"microsoft","product":"exchange_server"},{"vendor":"microsoft","product":"microsoft exchange server 2013 cumulative update 23"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 19"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 20"},{"vendor":"microsoft","product":"microsoft exchange server 2019 cumulative update 8"},{"vendor":"microsoft","product":"microsoft exchange server 2019 cumulative update 9"}],"references":[{"url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31209","tags":["x_refsource_MISC","x_transferred","Patch","Vendor Advisory"]},{"url":"https://www.zerodayinitiative.com/advisories/ZDI-21-615/","tags":["x_refsource_MISC","x_transferred","Third Party Advisory","VDB Entry"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-31209"},{"url":"https://www.zerodayinitiative.com/advisories/ZDI-21-615"},{"url":"https://github.com/advisories/GHSA-v623-3qmp-8rrh"}],"sources":{"cve":[{"id":"CVE-2021-31209","title":"Microsoft Exchange Server Spoofing Vulnerability","description":"Microsoft Exchange Server Spoofing Vulnerability","status":"published","published":"2021-05-11T19:11:43Z","modified":"2025-02-28T19:57:20.647Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N/E:U/RL:O/RC:C","level":"medium","assessor":"cna"}],"cwes":["CWE-290"],"updated_at":"2026-11-02T14:33:05.665371Z"}],"euvd":[{"id":"EUVD-2021-18122","description":"Microsoft Exchange Server Spoofing Vulnerability","status":"published","published":"2021-05-11T19:11:43Z","modified":"2025-02-28T19:57:20Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N/E:U/RL:O/RC:C","level":"medium"}],"updated_at":"2026-11-02T20:53:19.492993Z"}],"ghsa":[{"id":"GHSA-v623-3qmp-8rrh","title":"Microsoft Exchange Server Spoofing Vulnerability","description":"Microsoft Exchange Server Spoofing Vulnerability","status":"published","published":"2022-05-24T19:01:59Z","modified":"2025-02-28T21:32:57Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N","level":"high"}],"cwes":["CWE-290"],"updated_at":"2026-11-02T15:00:05.58597Z"}],"nvd":[{"id":"CVE-2021-31209","description":"Microsoft Exchange Server Spoofing Vulnerability","status":"published","published":"2021-05-11T19:15:10.467Z","modified":"2026-06-17T03:51:27.37Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N","level":"medium","assessor":"secondary"},{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N","level":"high","assessor":"secondary"},{"version":"2.0","score":5.8,"vector":"AV:N/AC:M/Au:N/C:P/I:P/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-290"],"updated_at":"2026-11-02T14:06:53.343329Z"}]}}