Security advisory

{
  "id": "0d18ed91c40ed3be1538dc7ad516e81db8dc6eed32b2cf5328a833ac2db509d7",
  "url": "https://osv.dev/vulnerability/CVE-2016-20012",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2016-20012",
    "summary": "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",
    "evidence": "osv:CVE-2016-20012",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2016-20012",
      "aliases": [
        "CVE-2016-20012"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/openssh/openssh-portable",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "e1a596186c81e65a34ce13076449712d3bf97eb4"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:openbsd:openssh:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "8.7"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "V_8_7_P1",
            "V_8_6_P1",
            "V_8_5_P1",
            "V_8_4_P1",
            "V_8_2_P1",
            "V_8_1_P1",
            "V_8_0_P1",
            "V_7_9_P1",
            "V_7_8_P1",
            "V_7_7_P1",
            "V_7_6_P1",
            "V_7_5_P1",
            "V_7_4_P1",
            "V_7_3_P1",
            "V_7_2_P1",
            "V_7_1_P1",
            "V_7_0_P1",
            "V_6_9_P1",
            "V_6_8_P1",
            "V_6_6_P1",
            "V_6_5_P1",
            "V_6_2_P1",
            "V_6_1_P1",
            "V_6_0_P1",
            "V_5_7_P1",
            "V_5_5_P1",
            "V_5_2_P1",
            "V_5_1_P1",
            "V_5_0_P1",
            "V_4_2_P1",
            "V_3_9_P1",
            "V_3_8_P1",
            "AFTER_KRB5_GSSAPI_MERGE",
            "BEFORE_KRB5_GSSAPI_MERGE",
            "POST_KRB4_REMOVAL",
            "PRE_KRB4_REMOVAL",
            "AFTER_FREEBSD_PAM_MERGE",
            "BEFORE_FREEBSD_PAM_MERGE",
            "V_3_6_1_P1",
            "V_3_4_P1",
            "V_3_2_2_P1",
            "PRE_SW_KRBV",
            "V_3_1_P1",
            "V_3_0_1_P1",
            "V_3_0_P1",
            "V_2_5_2_P1",
            "V_2_5_1_P2",
            "V_2_5_1_P1",
            "V_2_5_0_P1",
            "PRE-REORDER",
            "V_2_3_0_P1",
            "PRE_CYGWIN_MERGE",
            "V_2_2_0_P1",
            "V_2_1_1_P4",
            "V_2_1_1_P3",
            "ABOUT_TO_ADD_INET_ATON",
            "V_2_1_1_P2",
            "V_2_1_1_P1",
            "PRE_NEW_LOGIN_CODE",
            "V_2_1_0_P3",
            "V_2_1_0_P2",
            "V_2_1_0_P1",
            "V_2_1_0",
            "V_2_0_0_BETA2",
            "V_2_0_0_BETA1",
            "V_2_0_0_TEST1",
            "V_1_2_3_TEST3",
            "V_1_2_3_TEST2",
            "V_1_2_3_TEST1",
            "V_1_2_3",
            "V_1_2_3_PRE5",
            "V_1_2_3_PRE4",
            "V_1_2_3_PRE3",
            "V_1_2_3_PRE2",
            "V_1_2_3_PRE1",
            "V_1_2_2_P1",
            "V_1_2_2",
            "V_1_2_2_PRE29",
            "V_1_2_2_PRE28",
            "V_1_2_1_PRE27",
            "V_1_2_1_PRE26",
            "PRE_IPV6",
            "V_1_2_1_PRE25",
            "V_1_2_1_PRE24",
            "V_1_2_1_PRE23",
            "V_1_2_1_PRE22",
            "PRE_FIXPATHS_INTEGRATION",
            "V_1_2_1_PRE21",
            "V_1_2_1_PRE20",
            "V_1_2_1_PRE19",
            "PRE_HPUX_INTEGRATION",
            "V_1_2_1_PRE18",
            "V_1_2PRE17",
            "V_1_2_PRE16",
            "V_1_2_PRE15",
            "V_1_2_PRE14",
            "V_1_2_PRE13",
            "V_1_2_PRE12",
            "V_1_2_PRE11",
            "V_1_2_PRE10",
            "V_1_2_PRE9",
            "V_1_2_PRE8",
            "V_1_2_PRE7",
            "V_1_2_PRE6",
            "V_1_2_PRE5",
            "V_1_2_PRE4",
            "PRE_DAN_PATCH_MERGE"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2016-20012.json"
          }
        }
      ],
      "modified": "2026-10-20T10:47:35.611255641Z",
      "provider": "osv",
      "references": [
        "https://security.netapp.com/advisory/ntap-20211014-0005/",
        "https://utcc.utoronto.ca/~cks/space/blog/tech/SSHKeysAreInfoLeak",
        "https://www.openwall.com/lists/oss-security/2018/08/24/1",
        "https://github.com/openssh/openssh-portable/pull/270#issuecomment-920577097",
        "https://github.com/openssh/openssh-portable/pull/270#issuecomment-943909185",
        "https://github.com/openssh/openssh-portable/pull/270",
        "https://github.com/openssh/openssh-portable/blob/d0fffc88c8fe90c1815c6f4097bc8cbcabc0f3dd/auth2-pubkey.c#L261-L265",
        "https://rushter.com/blog/public-ssh-keys/"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2016-20012",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 379554,
  "published_at": "2021-09-15T20:15:07.31+00:00"
}