{"id":"CVE-2021-34453","aliases":["EUVD-2021-21108","GHSA-jh7x-v5rp-ggfr"],"status":"published","title":"Microsoft Exchange Server Denial of Service Vulnerability","description":"Microsoft Exchange Server Denial of Service Vulnerability","severity":{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.02826,"percentile":0.86776,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"published":"2021-10-13T00:26:37Z","modified":"2026-06-17T03:55:53Z","products":[{"vendor":"microsoft","product":"exchange_server"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 21"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 22"},{"vendor":"microsoft","product":"microsoft exchange server 2019 cumulative update 10"},{"vendor":"microsoft","product":"microsoft exchange server 2019 cumulative update 11"}],"references":[{"url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34453","tags":["x_refsource_MISC","x_transferred","Patch","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-34453"},{"url":"https://github.com/advisories/GHSA-jh7x-v5rp-ggfr"}],"sources":{"cve":[{"id":"CVE-2021-34453","title":"Microsoft Exchange Server Denial of Service Vulnerability","description":"Microsoft Exchange Server Denial of Service Vulnerability","status":"published","published":"2021-10-13T00:26:37Z","modified":"2024-08-04T00:12:50.102Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C","level":"high","assessor":"cna"}],"updated_at":"2026-11-02T14:33:11.59359Z"}],"euvd":[{"id":"EUVD-2021-21108","description":"Microsoft Exchange Server Denial of Service Vulnerability","status":"published","published":"2021-10-13T00:26:37Z","modified":"2024-08-04T00:12:50Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C","level":"high"}],"updated_at":"2026-11-03T03:24:32.445199Z"}],"ghsa":[{"id":"GHSA-jh7x-v5rp-ggfr","title":"Microsoft Exchange Server Denial of Service Vulnerability","description":"Microsoft Exchange Server Denial of Service Vulnerability","status":"published","published":"2022-05-24T19:17:34Z","modified":"2023-08-10T05:05:10Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T14:54:44.654498Z"}],"nvd":[{"id":"CVE-2021-34453","description":"Microsoft Exchange Server Denial of Service Vulnerability","status":"published","published":"2021-10-13T01:15:09.373Z","modified":"2026-06-17T03:55:53.857Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"secondary"},{"version":"2.0","score":5,"vector":"AV:N/AC:L/Au:N/C:N/I:N/A:P","level":"medium","assessor":"primary"}],"updated_at":"2026-11-02T14:06:59.689345Z"}]}}