{"id":"CVE-2021-36368","aliases":["ALPINE-CVE-2021-36368","AZL-9045","BELL-CVE-2021-36368","DEBIAN-CVE-2021-36368","EUVD-2021-22988","GHSA-542x-jxrc-hw4x"],"status":"disputed","title":"** DISPUTED ** An issue was discovered in OpenSSH before 8.9. If a client is using public-key...","description":"An issue was discovered in OpenSSH before 8.9. If a client is using public-key authentication with agent forwarding but without -oLogLevel=verbose, and an attacker has silently modified the server to support the None authentication option, then the user cannot determine whether FIDO authentication is going to confirm that the user wishes to connect to that server, or that the user wishes to allow that server to connect to a different server on the user's behalf. NOTE: the vendor's position is \"this is not an authentication bypass, since nothing is being bypassed.","severity":{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-11","score":0.01677,"percentile":0.77191,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-287"],"published":"2022-03-12T23:24:35Z","modified":"2026-10-24T10:50:42Z","fixes":[{"ecosystem":"Alpine:v3.19","package":"openssh","fixed_in":["8.9_p1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.20","package":"openssh","fixed_in":["8.9_p1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.21","package":"openssh","fixed_in":["8.9_p1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.22","package":"openssh","fixed_in":["8.9_p1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.23","package":"openssh","fixed_in":["8.9_p1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.24","package":"openssh","fixed_in":["8.9_p1-r0"],"sources":["osv"]},{"ecosystem":"Azure Linux:2","package":"openssh","fixed_in":["8.9p1-1"],"sources":["osv"]},{"ecosystem":"Debian:12","package":"openssh","fixed_in":["1:8.9p1-1"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"openssh","fixed_in":["1:8.9p1-1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"openssh","fixed_in":["1:8.9p1-1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Alpine:v3.19","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.9_p1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.20","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.9_p1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.21","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.9_p1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.22","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.9_p1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.23","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.9_p1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.24","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.9_p1-r0"}]}]},{"source":"osv","ecosystem":"Azure Linux:2","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.9p1-1"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:8.9p1-1"}]}]},{"source":"osv","ecosystem":"Debian:13","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:8.9p1-1"}]}]},{"source":"osv","ecosystem":"Debian:14","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:8.9p1-1"}]}]}],"products":[{"vendor":"debian","product":"debian_linux"},{"vendor":"openbsd","product":"openssh"}],"references":[{"url":"https://www.openssh.com/security.html","tags":["x_refsource_MISC","x_transferred","Vendor Advisory","advisory"]},{"url":"https://github.com/openssh/openssh-portable/pull/258","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","fix"]},{"url":"https://bugzilla.mindrot.org/show_bug.cgi?id=3316","tags":["x_refsource_CONFIRM","x_transferred","Issue Tracking","Third Party Advisory","report"]},{"url":"https://docs.ssh-mitm.at/trivialauth.html","tags":["x_refsource_MISC","x_transferred","Third Party Advisory","advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2021-36368","tags":["x_refsource_MISC","x_transferred","Third Party Advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-36368","tags":["web"]},{"url":"https://github.com/advisories/GHSA-542x-jxrc-hw4x"},{"url":"https://security.alpinelinux.org/vuln/CVE-2021-36368","tags":["advisory"]},{"url":"https://docs.bell-sw.com/security/cves/CVE-2021-36368","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2021-36368","description":"An issue was discovered in OpenSSH before 8.9. If a client is using public-key authentication with agent forwarding but without -oLogLevel=verbose, and an attacker has silently modified the server to support the None authentication option, then the user cannot determine whether FIDO authentication is going to confirm that the user wishes to connect to that server, or that the user wishes to allow that server to connect to a different server on the user's behalf. NOTE: the vendor's position is \"this is not an authentication bypass, since nothing is being bypassed.","status":"disputed","published":"2022-03-12T23:24:35Z","modified":"2026-05-29T18:46:21.545Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"adp"}],"cwes":["CWE-287"],"updated_at":"2026-11-02T14:33:05.989686Z"}],"euvd":[{"id":"EUVD-2021-22988","description":"An issue was discovered in OpenSSH before 8.9. If a client is using public-key authentication with agent forwarding but without -oLogLevel=verbose, and an attacker has silently modified the server to support the None authentication option, then the user cannot determine whether FIDO authentication is going to confirm that the user wishes to connect to that server, or that the user wishes to allow that server to connect to a different server on the user's behalf. NOTE: the vendor's position is \"this is not an authentication bypass, since nothing is being bypassed.","status":"published","published":"2022-03-12T23:24:35Z","modified":"2026-05-29T18:46:21Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-02T18:21:00.384456Z"}],"ghsa":[{"id":"GHSA-542x-jxrc-hw4x","title":"** DISPUTED ** An issue was discovered in OpenSSH before 8.9. If a client is using public-key...","description":"** DISPUTED ** An issue was discovered in OpenSSH before 8.9. If a client is using public-key authentication with agent forwarding but without -oLogLevel=verbose, and an attacker has silently modified the server to support the None authentication option, then the user cannot determine whether FIDO authentication is going to confirm that the user wishes to connect to that server, or that the user wishes to allow that server to connect to a different server on the user's behalf. NOTE: the vendor's position is \"this is not an authentication bypass, since nothing is being bypassed.\"","status":"published","published":"2022-03-14T00:00:21Z","modified":"2023-01-27T05:00:41Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"cwes":["CWE-287"],"updated_at":"2026-11-02T14:41:43.766328Z"}],"nvd":[{"id":"CVE-2021-36368","description":"An issue was discovered in OpenSSH before 8.9. If a client is using public-key authentication with agent forwarding but without -oLogLevel=verbose, and an attacker has silently modified the server to support the None authentication option, then the user cannot determine whether FIDO authentication is going to confirm that the user wishes to connect to that server, or that the user wishes to allow that server to connect to a different server on the user's behalf. NOTE: the vendor's position is \"this is not an authentication bypass, since nothing is being bypassed.","status":"disputed","published":"2022-03-13T00:15:07.937Z","modified":"2026-06-17T03:58:45.34Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"primary"},{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"secondary"},{"version":"2.0","score":2.6,"vector":"AV:N/AC:H/Au:N/C:P/I:N/A:N","level":"low","assessor":"primary"}],"cwes":["CWE-287"],"updated_at":"2026-11-02T14:07:05.198719Z"}],"osv":[{"id":"ALPINE-CVE-2021-36368","description":"An issue was discovered in OpenSSH before 8.9. If a client is using public-key authentication with agent forwarding but without -oLogLevel=verbose, and an attacker has silently modified the server to support the None authentication option, then the user cannot determine whether FIDO authentication is going to confirm that the user wishes to connect to that server, or that the user wishes to allow that server to connect to a different server on the user's behalf. NOTE: the vendor's position is \"this is not an authentication bypass, since nothing is being bypassed.","status":"published","published":"2022-03-13T00:15:07.937Z","modified":"2026-10-23T17:17:56.199956151Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-02T15:27:48.646074Z"},{"id":"AZL-9045","title":"CVE-2021-36368 affecting package openssh for versions less than 8.9p1-1","description":"An issue was discovered in OpenSSH before 8.9. If a client is using public-key authentication with agent forwarding but without -oLogLevel=verbose, and an attacker has silently modified the server to support the None authentication option, then the user cannot determine whether FIDO authentication is going to confirm that the user wishes to connect to that server, or that the user wishes to allow that server to connect to a different server on the user's behalf. NOTE: the vendor's position is \"this is not an authentication bypass, since nothing is being bypassed.","status":"published","published":"2022-03-13T00:15:07Z","modified":"2026-04-21T04:34:58.498112Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-02T15:28:11.397546Z"},{"id":"BELL-CVE-2021-36368","title":"CVE-2021-36368 does not affect BellSoft software","status":"withdrawn","published":"2022-03-13T00:15:00Z","modified":"2026-01-26T09:48:17.433381Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-02T15:28:16.5265Z"},{"id":"CVE-2021-36368","description":"An issue was discovered in OpenSSH before 8.9. If a client is using public-key authentication with agent forwarding but without -oLogLevel=verbose, and an attacker has silently modified the server to support the None authentication option, then the user cannot determine whether FIDO authentication is going to confirm that the user wishes to connect to that server, or that the user wishes to allow that server to connect to a different server on the user's behalf. NOTE: the vendor's position is \"this is not an authentication bypass, since nothing is being bypassed.","status":"published","published":"2022-03-13T00:15:07.937Z","modified":"2026-10-24T10:50:42.302468539Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-02T15:44:20.434873Z"},{"id":"DEBIAN-CVE-2021-36368","description":"An issue was discovered in OpenSSH before 8.9. If a client is using public-key authentication with agent forwarding but without -oLogLevel=verbose, and an attacker has silently modified the server to support the None authentication option, then the user cannot determine whether FIDO authentication is going to confirm that the user wishes to connect to that server, or that the user wishes to allow that server to connect to a different server on the user's behalf. NOTE: the vendor's position is \"this is not an authentication bypass, since nothing is being bypassed.","status":"published","published":"2022-03-13T00:15:07.937Z","modified":"2026-10-23T18:04:50.774418002Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-02T15:45:35.233346Z"}]}}