{"id":"CVE-2016-20012","aliases":["BELL-CVE-2016-20012","DEBIAN-CVE-2016-20012","EUVD-2016-3100","GHSA-84j4-ccmw-hwpg","UBUNTU-CVE-2016-20012"],"status":"disputed","title":"OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of...","description":"OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of username and public key is known to an SSH server, to test whether this suspicion is correct. This occurs because a challenge is sent only when that combination could be valid for a login session. NOTE: the vendor does not recognize user enumeration as a vulnerability for this product","severity":{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-08","score":0.05326,"percentile":0.92665,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":true,"fix_available":false},"cwes":["CWE-203"],"published":"2021-09-15T19:32:11Z","modified":"2026-10-23T04:45:03Z","exploits":[{"source":"pocgithub","id":"arturo-b-cmu/cve-2016-20012","title":"arturo-b-cmu/cve-2016-20012","date":"2024-08-28","url":"https://github.com/arturo-b-cmu/cve-2016-20012"}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:10.0p1-1","1:10.0p1-2","1:10.0p1-3","1:10.0p1-4","1:10.0p1-5","1:10.0p1-5~bpo12+2","1:10.0p1-6","1:10.0p1-7","1:10.0p1-7~bpo12+1","1:10.0p1-8","1:10.1p1-1","1:10.1p1-2","1:10.2p1-1","1:10.2p1-2","1:10.2p1-2~bpo13+1","1:10.2p1-3","1:10.2p1-4","1:10.2p1-5","1:10.2p1-6","1:10.2p1-6~bpo13+1","1:10.3p1-1","1:10.3p1-1~bpo13+1","1:10.3p1-2","1:10.3p1-3","1:10.3p1-4","1:10.3p1-5","1:10.3p1-7","1:10.3p1-8","1:10.3p1-9","1:10.4p1-1","1:10.4p1-2","1:10.4p1-3","1:10.4p1-4","1:10.4p1-5","1:10.5p1-1","1:9.2p1-2","1:9.2p1-2+deb12u1","1:9.2p1-2+deb12u10","1:9.2p1-2+deb12u2","1:9.2p1-2+deb12u3","1:9.2p1-2+deb12u4","1:9.2p1-2+deb12u5","1:9.2p1-2+deb12u6","1:9.2p1-2+deb12u7","1:9.2p1-2+deb12u8","1:9.2p1-2+deb12u9","1:9.3p1-1","1:9.3p1-1+loong64","1:9.3p2-1","1:9.4p1-1","1:9.5p1-1","1:9.5p1-2","1:9.6p1-1","1:9.6p1-2","1:9.6p1-3","1:9.6p1-4","1:9.6p1-5","1:9.7p1-1","1:9.7p1-2","1:9.7p1-3","1:9.7p1-3+hurd.1","1:9.7p1-4","1:9.7p1-5","1:9.7p1-6","1:9.7p1-7","1:9.8p1-1","1:9.8p1-2","1:9.8p1-3","1:9.8p1-4","1:9.8p1-7","1:9.8p1-8","1:9.9p1-1","1:9.9p1-2","1:9.9p1-3","1:9.9p1-3+hurd.1","1:9.9p2-1","1:9.9p2-2"]},{"source":"osv","ecosystem":"Debian:13","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:10.0p1-7","1:10.0p1-7+deb13u1","1:10.0p1-7+deb13u2","1:10.0p1-7+deb13u3","1:10.0p1-7+deb13u4","1:10.0p1-8","1:10.1p1-1","1:10.1p1-2","1:10.2p1-1","1:10.2p1-2","1:10.2p1-2~bpo13+1","1:10.2p1-3","1:10.2p1-4","1:10.2p1-5","1:10.2p1-6","1:10.2p1-6~bpo13+1","1:10.3p1-1","1:10.3p1-1~bpo13+1","1:10.3p1-2","1:10.3p1-3","1:10.3p1-4","1:10.3p1-5","1:10.3p1-7","1:10.3p1-8","1:10.3p1-9","1:10.4p1-1","1:10.4p1-2","1:10.4p1-3","1:10.4p1-4","1:10.4p1-5","1:10.5p1-1"]},{"source":"osv","ecosystem":"Debian:14","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:10.0p1-7","1:10.0p1-8","1:10.1p1-1","1:10.1p1-2","1:10.2p1-1","1:10.2p1-2","1:10.2p1-2~bpo13+1","1:10.2p1-3","1:10.2p1-4","1:10.2p1-5","1:10.2p1-6","1:10.2p1-6~bpo13+1","1:10.3p1-1","1:10.3p1-1~bpo13+1","1:10.3p1-2","1:10.3p1-3","1:10.3p1-4","1:10.3p1-5","1:10.3p1-7","1:10.3p1-8","1:10.3p1-9","1:10.4p1-1","1:10.4p1-2","1:10.4p1-3","1:10.4p1-4","1:10.4p1-5","1:10.5p1-1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:14.04:LTS","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:6.2p2-6","1:6.2p2-6ubuntu1","1:6.4p1-1","1:6.4p1-2","1:6.5p1-1","1:6.5p1-2","1:6.5p1-3","1:6.5p1-4","1:6.5p1-6","1:6.6p1-1","1:6.6p1-2","1:6.6p1-2ubuntu1","1:6.6p1-2ubuntu2","1:6.6p1-2ubuntu2.2","1:6.6p1-2ubuntu2.3","1:6.6p1-2ubuntu2.4","1:6.6p1-2ubuntu2.6","1:6.6p1-2ubuntu2.7","1:6.6p1-2ubuntu2.8","1:6.6p1-2ubuntu2.10","1:6.6p1-2ubuntu2.11","1:6.6p1-2ubuntu2.12","1:6.6p1-2ubuntu2.13","1:6.6p1-2ubuntu2.13+esm1","1:6.6p1-2ubuntu2.13+esm2","1:6.6p1-2ubuntu2.13+esm3","1:6.6p1-2ubuntu2.13+esm4"]},{"source":"osv","ecosystem":"Ubuntu:Pro:16.04:LTS","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:6.9p1-2","1:6.9p1-3","1:7.1p1-1","1:7.1p1-3","1:7.1p1-4","1:7.1p1-6","1:7.1p2-1","1:7.1p2-2","1:7.2p1-1","1:7.2p2-1","1:7.2p2-2","1:7.2p2-3","1:7.2p2-4","1:7.2p2-4ubuntu1","1:7.2p2-4ubuntu2.1","1:7.2p2-4ubuntu2.2","1:7.2p2-4ubuntu2.4","1:7.2p2-4ubuntu2.5","1:7.2p2-4ubuntu2.6","1:7.2p2-4ubuntu2.7","1:7.2p2-4ubuntu2.8","1:7.2p2-4ubuntu2.10","1:7.2p2-4ubuntu2.10+esm1","1:7.2p2-4ubuntu2.10+esm2","1:7.2p2-4ubuntu2.10+esm3","1:7.2p2-4ubuntu2.10+esm4","1:7.2p2-4ubuntu2.10+esm5","1:7.2p2-4ubuntu2.10+esm6","1:7.2p2-4ubuntu2.10+esm7","1:7.2p2-4ubuntu2.10+esm8","1:7.2p2-4ubuntu2.10+esm9","1:7.2p2-4ubuntu2.10+esm10"]},{"source":"osv","ecosystem":"Ubuntu:Pro:FIPS-updates:16.04:LTS","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:7.2p2-4ubuntu2.fips.2.2.3","1:7.2p2-4ubuntu2.fips.2.4.1","1:7.2p2-4ubuntu2.fips.2.4.2","1:7.2p2-4ubuntu2.fips.2.8.1","1:7.2p2-4ubuntu2.fips.2.10.1","1:7.2p2-4ubuntu2.fips.2.10.2","1:7.2p2-4ubuntu2.fips.2.10.3","1:7.2p2-4ubuntu2.fips.2.10.4","1:7.2p2-4ubuntu2.fips.2.10.5","1:7.2p2-4ubuntu2.fips.2.10.6","1:7.2p2-4ubuntu2.fips.2.10.7"]},{"source":"osv","ecosystem":"Ubuntu:Pro:FIPS:16.04:LTS","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:7.2p2-4ubuntu2.fips.2.2","1:7.2p2-4ubuntu2.fips.2.2.1","1:7.2p2-4ubuntu2.fips.2.10.1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:7.5p1-10","1:7.6p1-4","1:7.6p1-4ubuntu0.1","1:7.6p1-4ubuntu0.2","1:7.6p1-4ubuntu0.3","1:7.6p1-4ubuntu0.5","1:7.6p1-4ubuntu0.6","1:7.6p1-4ubuntu0.7","1:7.6p1-4ubuntu0.7+esm1","1:7.6p1-4ubuntu0.7+esm2","1:7.6p1-4ubuntu0.7+esm3","1:7.6p1-4ubuntu0.7+esm4","1:7.6p1-4ubuntu0.7+esm5","1:7.6p1-4ubuntu0.7+esm6"]},{"source":"osv","ecosystem":"Ubuntu:18.04:LTS","package":"openssh-ssh1","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:7.5p1-8","1:7.5p1-9","1:7.5p1-9build1","1:7.5p1-10"]},{"source":"osv","ecosystem":"Ubuntu:Pro:FIPS-updates:18.04:LTS","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:7.9p1-10~ubuntu18.04.fips.0.1","1:7.9p1-10~ubuntu18.04.fips.0.2","1:7.9p1-10~ubuntu18.04.fips.0.3","1:7.9p1-10~ubuntu18.04.fips.0.4","1:7.9p1-10~ubuntu18.04.fips.0.5","1:7.9p1-10~ubuntu18.04.fips.0.6","1:7.9p1-10~ubuntu18.04.fips.0.7","1:7.9p1-10~ubuntu18.04.fips.0.8","1:7.9p1-10~ubuntu18.04.fips.0.9","1:7.9p1-10~ubuntu18.04.fips.0.10"]},{"source":"osv","ecosystem":"Ubuntu:Pro:FIPS:18.04:LTS","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:7.9p1-10~ubuntu18.04.fips.0.1","1:7.9p1-10~ubuntu18.04.fips.0.2"]},{"source":"osv","ecosystem":"Ubuntu:Pro:20.04:LTS","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:8.0p1-6build1","1:8.1p1-1","1:8.1p1-5","1:8.2p1-4","1:8.2p1-4ubuntu0.1","1:8.2p1-4ubuntu0.2","1:8.2p1-4ubuntu0.3","1:8.2p1-4ubuntu0.4","1:8.2p1-4ubuntu0.5","1:8.2p1-4ubuntu0.7","1:8.2p1-4ubuntu0.8","1:8.2p1-4ubuntu0.9","1:8.2p1-4ubuntu0.10","1:8.2p1-4ubuntu0.11","1:8.2p1-4ubuntu0.12","1:8.2p1-4ubuntu0.13","1:8.2p1-4ubuntu0.13+esm1","1:8.2p1-4ubuntu0.13+esm2","1:8.2p1-4ubuntu0.13+esm3"]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"openssh-ssh1","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:7.5p1-11build1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:FIPS-updates:20.04:LTS","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:8.2p1-4ubuntu0.fips.0.2.1","1:8.2p1-4ubuntu0.fips.0.4.0","1:8.2p1-4ubuntu0.fips.0.5.0","1:8.2p1-4ubuntu0.fips.0.7","1:8.2p1-4ubuntu0.fips.0.8","1:8.2p1-4ubuntu0.fips.0.9","1:8.2p1-4ubuntu0.fips.0.10","1:8.2p1-4ubuntu0.fips.0.11","1:8.2p1-4ubuntu0.fips.0.12","1:8.2p1-4ubuntu0.fips.0.13","1:8.2p1-4ubuntu0.fips.0.13.1","1:8.2p1-4ubuntu0.fips.0.13.3"]},{"source":"osv","ecosystem":"Ubuntu:Pro:FIPS:20.04:LTS","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:8.2p1-4ubuntu0.fips.0.2.1"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"openssh","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:8.4p1-6ubuntu2","1:8.7p1-2","1:8.7p1-2build1","1:8.7p1-4","1:8.8p1-1","1:8.9p1-3","1:8.9p1-3ubuntu0.1","1:8.9p1-3ubuntu0.3","1:8.9p1-3ubuntu0.4","1:8.9p1-3ubuntu0.5","1:8.9p1-3ubuntu0.6","1:8.9p1-3ubuntu0.7","1:8.9p1-3ubuntu0.10","1:8.9p1-3ubuntu0.11","1:8.9p1-3ubuntu0.13","1:8.9p1-3ubuntu0.14","1:8.9p1-3ubuntu0.15","1:8.9p1-3ubuntu0.16","1:8.9p1-3ubuntu0.17","1:8.9p1-3ubuntu0.18"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"openssh-ssh1","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:7.5p1-12","1:7.5p1-12build1","1:7.5p1-13"]}],"products":[{"vendor":"netapp","product":"clustered_data_ontap"},{"vendor":"netapp","product":"hci_management_node"},{"vendor":"netapp","product":"ontap_select_deploy_administration_utility"},{"vendor":"netapp","product":"solidfire"},{"vendor":"openbsd","product":"openssh"}],"references":[{"url":"https://github.com/openssh/openssh-portable/pull/270","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","fix","report"]},{"url":"https://github.com/openssh/openssh-portable/blob/d0fffc88c8fe90c1815c6f4097bc8cbcabc0f3dd/auth2-pubkey.c#L261-L265","tags":["x_refsource_MISC","x_transferred","exploit","Exploit","Third Party Advisory","evidence","report"]},{"url":"https://utcc.utoronto.ca/~cks/space/blog/tech/SSHKeysAreInfoLeak","tags":["x_refsource_MISC","x_transferred","Third Party Advisory","advisory","report"]},{"url":"https://rushter.com/blog/public-ssh-keys/","tags":["x_refsource_MISC","x_transferred","Exploit","Third Party Advisory","evidence","report"]},{"url":"https://security.netapp.com/advisory/ntap-20211014-0005/","tags":["x_refsource_CONFIRM","x_transferred","Third Party Advisory","advisory"]},{"url":"https://github.com/openssh/openssh-portable/pull/270#issuecomment-920577097","tags":["x_refsource_MISC","x_transferred","Issue Tracking","Third Party Advisory","report"]},{"url":"https://www.openwall.com/lists/oss-security/2018/08/24/1","tags":["x_refsource_MISC","x_transferred","Mailing List","Third Party Advisory","advisory"]},{"url":"https://github.com/openssh/openssh-portable/pull/270#issuecomment-943909185","tags":["x_refsource_MISC","x_transferred","Issue Tracking","Third Party Advisory","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2016-20012"},{"url":"https://rushter.com/blog/public-ssh-keys"},{"url":"https://security.netapp.com/advisory/ntap-20211014-0005"},{"url":"https://github.com/advisories/GHSA-84j4-ccmw-hwpg"},{"url":"https://docs.bell-sw.com/security/cves/CVE-2016-20012","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2016-20012","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2016-20012","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2016-20012","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2016-20012","description":"OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of username and public key is known to an SSH server, to test whether this suspicion is correct. This occurs because a challenge is sent only when that combination could be valid for a login session. NOTE: the vendor does not recognize user enumeration as a vulnerability for this product","status":"disputed","published":"2021-09-15T19:32:11Z","modified":"2026-05-29T15:38:31.136Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"adp"}],"cwes":["CWE-203"],"updated_at":"2026-11-02T14:33:30.359814Z"}],"euvd":[{"id":"EUVD-2016-3100","description":"OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of username and public key is known to an SSH server, to test whether this suspicion is correct. This occurs because a challenge is sent only when that combination could be valid for a login session. NOTE: the vendor does not recognize user enumeration as a vulnerability for this product","status":"published","published":"2021-09-15T19:32:11Z","modified":"2026-05-29T15:38:31Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T18:21:00.772434Z"}],"ghsa":[{"id":"GHSA-84j4-ccmw-hwpg","title":"OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of...","description":"OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of username and public key is known to an SSH server, to test whether this suspicion is correct. This occurs because a challenge is sent only when that combination could be valid for a login session.","status":"published","published":"2022-05-24T19:14:33Z","modified":"2026-05-29T18:31:14Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"cwes":["CWE-203"],"updated_at":"2026-11-02T15:08:23.402135Z"}],"nvd":[{"id":"CVE-2016-20012","description":"OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of username and public key is known to an SSH server, to test whether this suspicion is correct. This occurs because a challenge is sent only when that combination could be valid for a login session. NOTE: the vendor does not recognize user enumeration as a vulnerability for this product","status":"disputed","published":"2021-09-15T20:15:07.31Z","modified":"2026-06-17T00:43:05.063Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"primary"},{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"secondary"},{"version":"2.0","score":4.3,"vector":"AV:N/AC:M/Au:N/C:P/I:N/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-203"],"updated_at":"2026-11-02T14:03:40.524348Z"}],"osv":[{"id":"BELL-CVE-2016-20012","title":"CVE-2016-20012 does not affect BellSoft software","status":"withdrawn","published":"2021-09-15T20:15:00Z","modified":"2026-01-26T09:48:31.875898Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T15:28:13.47097Z"},{"id":"CVE-2016-20012","description":"OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of username and public key is known to an SSH server, to test whether this suspicion is correct. This occurs because a challenge is sent only when that combination could be valid for a login session. NOTE: the vendor does not recognize user enumeration as a vulnerability for this product","status":"published","published":"2021-09-15T20:15:07.31Z","modified":"2026-10-20T10:47:35.611255641Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T15:44:02.114472Z"},{"id":"DEBIAN-CVE-2016-20012","description":"OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of username and public key is known to an SSH server, to test whether this suspicion is correct. This occurs because a challenge is sent only when that combination could be valid for a login session. NOTE: the vendor does not recognize user enumeration as a vulnerability for this product","status":"published","published":"2021-09-15T20:15:07.31Z","modified":"2026-09-22T07:01:26.763678346Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T15:45:27.323751Z"},{"id":"UBUNTU-CVE-2016-20012","description":"OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of username and public key is known to an SSH server, to test whether this suspicion is correct. This occurs because a challenge is sent only when that combination could be valid for a login session. NOTE: the vendor does not recognize user enumeration as a vulnerability for this product","status":"published","published":"2021-09-15T20:15:00Z","modified":"2026-10-23T04:45:03.361553756Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"},{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T15:54:11.492576Z"}]}}