{"id":"CVE-2021-32566","aliases":["DEBIAN-CVE-2021-32566","DSA-4957-1","EUVD-2021-19408","GHSA-8cqh-mhwj-8g3v","UBUNTU-CVE-2021-32566"],"status":"published","title":"Specific sequence of HTTP/2 frames can cause ATS to crash","description":"Improper Input Validation vulnerability in HTTP/2 of Apache Traffic Server allows an attacker to DOS the server. This issue affects Apache Traffic Server 7.0.0 to 7.1.12, 8.0.0 to 8.1.1, 9.0.0 to 9.0.1.","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","level":"high","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-10","score":0.02447,"percentile":0.84483,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-20"],"published":"2021-06-30T07:15:19Z","modified":"2026-10-24T10:30:50Z","fixes":[{"ecosystem":"Debian:12","package":"trafficserver","fixed_in":["8.1.1+ds-1.1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"trafficserver","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.1.1+ds-1.1"}]}]},{"source":"osv","ecosystem":"Debian:10","package":"trafficserver","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.0.2+ds-1+deb10u5"}]}],"versions":["8.0.2+ds-1","8.0.2+ds-1+deb10u1","8.0.2+ds-1+deb10u2","8.0.2+ds-1+deb10u3","8.0.2+ds-1+deb10u4"],"bundled":5},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"trafficserver","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.3.0-2ubuntu1","5.3.0-2ubuntu2"]},{"source":"osv","ecosystem":"Ubuntu:18.04:LTS","package":"trafficserver","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["7.0.0-5","7.1.2+ds-2","7.1.2+ds-2build1","7.1.2+ds-3"]},{"source":"osv","ecosystem":"Ubuntu:Pro:20.04:LTS","package":"trafficserver","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["8.0.5+ds-1","8.0.5+ds-2","8.0.5+ds-2build1","8.0.5+ds-2ubuntu1","8.0.5+ds-3","8.0.5+ds-3ubuntu0.1~esm1"]}],"products":[{"vendor":"apache","product":"traffic_server"},{"vendor":"apache software foundation","product":"apache traffic server"},{"vendor":"debian","product":"debian_linux"}],"references":[{"url":"https://lists.apache.org/thread.html/ra1a41ff92a70d25bf576d7da2590575e8ff430393a3f4a0c34de4277%40%3Cusers.trafficserver.apache.org%3E","tags":["x_refsource_MISC","x_transferred","Mailing List","Vendor Advisory","advisory"]},{"url":"https://www.debian.org/security/2021/dsa-4957","tags":["vendor-advisory","x_refsource_DEBIAN","x_transferred","Third Party Advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-32566"},{"url":"https://github.com/advisories/GHSA-8cqh-mhwj-8g3v"},{"url":"https://security-tracker.debian.org/tracker/CVE-2021-32566","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2021-32566","tags":["report"]},{"url":"https://lists.apache.org/thread.html/ra1a41ff92a70d25bf576d7da2590575e8ff430393a3f4a0c34de4277%40%3Cannounce.trafficserver.apache.org%3E","tags":["report"]},{"url":"https://github.com/apache/trafficserver/pull/7945","tags":["report"]},{"url":"https://github.com/apache/trafficserver/commit/034965e0fd0def114658f0048d953d1c16a95bed","tags":["report"]},{"url":"https://github.com/apache/trafficserver/commit/b82a3d192f995fb9d78e1c44d51d9acca4783277","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-32566","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2021-32566","title":"Specific sequence of HTTP/2 frames can cause ATS to crash","description":"Improper Input Validation vulnerability in HTTP/2 of Apache Traffic Server allows an attacker to DOS the server. This issue affects Apache Traffic Server 7.0.0 to 7.1.12, 8.0.0 to 8.1.1, 9.0.0 to 9.0.1.","status":"published","published":"2021-06-30T07:15:19Z","modified":"2024-08-03T23:25:30.377Z","cwes":["CWE-20"],"updated_at":"2026-11-02T14:33:07.349244Z"}],"euvd":[{"id":"EUVD-2021-19408","description":"Improper Input Validation vulnerability in HTTP/2 of Apache Traffic Server allows an attacker to DOS the server. This issue affects Apache Traffic Server 7.0.0 to 7.1.12, 8.0.0 to 8.1.1, 9.0.0 to 9.0.1.","status":"published","published":"2021-06-30T07:15:19Z","modified":"2024-08-03T23:25:30Z","updated_at":"2026-11-03T03:24:36.41075Z"}],"ghsa":[{"id":"GHSA-8cqh-mhwj-8g3v","title":"Improper Input Validation vulnerability in HTTP/2 of Apache Traffic Server allows an attacker to...","description":"Improper Input Validation vulnerability in HTTP/2 of Apache Traffic Server allows an attacker to DOS the server. This issue affects Apache Traffic Server 7.0.0 to 7.1.12, 8.0.0 to 8.1.1, 9.0.0 to 9.0.1.","status":"published","published":"2022-05-24T19:06:41Z","modified":"2023-01-30T05:00:35Z","cwes":["CWE-20"],"updated_at":"2026-11-02T14:46:14.069279Z"}],"nvd":[{"id":"CVE-2021-32566","description":"Improper Input Validation vulnerability in HTTP/2 of Apache Traffic Server allows an attacker to DOS the server. This issue affects Apache Traffic Server 7.0.0 to 7.1.12, 8.0.0 to 8.1.1, 9.0.0 to 9.0.1.","status":"published","published":"2021-06-30T08:15:06.737Z","modified":"2026-06-17T03:53:11.14Z","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":"primary"},{"version":"2.0","score":5,"vector":"AV:N/AC:L/Au:N/C:N/I:N/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T14:06:55.259633Z"}],"osv":[{"id":"CVE-2021-32566","description":"Improper Input Validation vulnerability in HTTP/2 of Apache Traffic Server allows an attacker to DOS the server. This issue affects Apache Traffic Server 7.0.0 to 7.1.12, 8.0.0 to 8.1.1, 9.0.0 to 9.0.1.","status":"published","published":"2021-06-30T08:15:06.737Z","modified":"2026-10-24T10:30:50.691545845Z","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":"2026-11-02T15:44:19.793849Z"},{"id":"DEBIAN-CVE-2021-32566","description":"Improper Input Validation vulnerability in HTTP/2 of Apache Traffic Server allows an attacker to DOS the server. This issue affects Apache Traffic Server 7.0.0 to 7.1.12, 8.0.0 to 8.1.1, 9.0.0 to 9.0.1.","status":"published","published":"2021-06-30T08:15:06.737Z","modified":"2026-10-23T18:03:49.070362087Z","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":"2026-11-02T15:45:35.233346Z"},{"id":"UBUNTU-CVE-2021-32566","description":"Improper Input Validation vulnerability in HTTP/2 of Apache Traffic Server allows an attacker to DOS the server. This issue affects Apache Traffic Server 7.0.0 to 7.1.12, 8.0.0 to 8.1.1, 9.0.0 to 9.0.1.","status":"published","published":"2021-06-30T08:15:00Z","modified":"2026-04-22T12:53:59.833813Z","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":"2026-11-02T15:54:27.332852Z"},{"id":"DSA-4957-1","title":"trafficserver - security update","status":"published","published":"2021-08-13T00:00:00Z","modified":"2026-03-09T02:09:06.416343Z","updated_at":"2026-11-02T15:46:17.19998Z"}]}}