{"id":"CVE-2021-40083","aliases":["DEBIAN-CVE-2021-40083","EUVD-2021-27273","GHSA-wvjr-27w9-ff2r","UBUNTU-CVE-2021-40083"],"status":"published","title":"Knot Resolver before 5.3.2 is prone to an assertion failure, triggerable by a remote attacker in...","description":"Knot Resolver before 5.3.2 is prone to an assertion failure, triggerable by a remote attacker in an edge case (NSEC3 with too many iterations used for a positive wildcard proof).","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":"2026-11-11","score":0.01421,"percentile":0.7319,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-617"],"published":"2021-08-25T00:21:43Z","modified":"2026-10-24T10:30:39Z","fixes":[{"ecosystem":"Debian:12","package":"knot-resolver","fixed_in":["5.4.1-2"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"knot-resolver","fixed_in":["5.4.1-2"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"knot-resolver","fixed_in":["5.4.1-2"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"knot-resolver","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.4.1-2"}]}]},{"source":"osv","ecosystem":"Debian:13","package":"knot-resolver","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.4.1-2"}]}]},{"source":"osv","ecosystem":"Debian:14","package":"knot-resolver","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.4.1-2"}]}]}],"products":[{"vendor":"nic","product":"knot_resolver"}],"references":[{"url":"https://gitlab.nic.cz/knot/knot-resolver/-/merge_requests/1169","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","fix","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-40083"},{"url":"https://github.com/advisories/GHSA-wvjr-27w9-ff2r"},{"url":"https://security-tracker.debian.org/tracker/CVE-2021-40083","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2021-40083","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-40083","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2021-40083","description":"Knot Resolver before 5.3.2 is prone to an assertion failure, triggerable by a remote attacker in an edge case (NSEC3 with too many iterations used for a positive wildcard proof).","status":"published","published":"2021-08-25T00:21:43Z","modified":"2024-08-04T02:27:31.802Z","updated_at":"2026-11-02T14:33:01.495293Z"}],"euvd":[{"id":"EUVD-2021-27273","description":"Knot Resolver before 5.3.2 is prone to an assertion failure, triggerable by a remote attacker in an edge case (NSEC3 with too many iterations used for a positive wildcard proof).","status":"published","published":"2021-08-25T00:21:43Z","modified":"2024-08-04T02:27:31Z","updated_at":"2026-11-03T03:24:21.368958Z"}],"ghsa":[{"id":"GHSA-wvjr-27w9-ff2r","title":"Knot Resolver before 5.3.2 is prone to an assertion failure, triggerable by a remote attacker in...","description":"Knot Resolver before 5.3.2 is prone to an assertion failure, triggerable by a remote attacker in an edge case (NSEC3 with too many iterations used for a positive wildcard proof).","status":"published","published":"2022-05-24T19:12:14Z","modified":"2023-01-30T05:01:48Z","cwes":["CWE-617"],"updated_at":"2026-11-02T14:46:29.327755Z"}],"nvd":[{"id":"CVE-2021-40083","description":"Knot Resolver before 5.3.2 is prone to an assertion failure, triggerable by a remote attacker in an edge case (NSEC3 with too many iterations used for a positive wildcard proof).","status":"published","published":"2021-08-25T01:15:11.087Z","modified":"2026-06-17T04:06:29.363Z","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-617"],"updated_at":"2026-11-02T14:06:57.67549Z"}],"osv":[{"id":"CVE-2021-40083","description":"Knot Resolver before 5.3.2 is prone to an assertion failure, triggerable by a remote attacker in an edge case (NSEC3 with too many iterations used for a positive wildcard proof).","status":"published","published":"2021-08-25T01:15:11.087Z","modified":"2026-10-24T10:30:39.95491984Z","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":"2026-11-02T15:44:21.249056Z"},{"id":"DEBIAN-CVE-2021-40083","description":"Knot Resolver before 5.3.2 is prone to an assertion failure, triggerable by a remote attacker in an edge case (NSEC3 with too many iterations used for a positive wildcard proof).","status":"published","published":"2021-08-25T01:15:11.087Z","modified":"2026-10-23T18:03:32.647562293Z","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":"2026-11-02T15:45:35.521549Z"},{"id":"UBUNTU-CVE-2021-40083","description":"Knot Resolver before 5.3.2 is prone to an assertion failure, triggerable by a remote attacker in an edge case (NSEC3 with too many iterations used for a positive wildcard proof).","status":"withdrawn","published":"2021-08-25T01:15:00Z","modified":"2025-07-16T07:43:13.770156Z","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":"2026-11-02T15:54:28.526929Z"}]}}