Security advisory

{
  "id": "bca8faf1187c73368747db2dc844d7f82c8f9ede42c59db263c9b2aa6585a73f",
  "url": "https://osv.dev/vulnerability/CVE-2021-36369",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-36369",
    "summary": "An issue was discovered in Dropbear through 2020.81. Due to a non-RFC-compliant check of the available authentication methods in the client-side SSH code, it is possible for an SSH server to change the login process in its favor. This attack can bypass additional security measures such as FIDO2 tokens or SSH-Askpass. Thus, it allows an attacker to abuse a forwarded agent for logging on to another server unnoticed.",
    "evidence": "osv:CVE-2021-36369",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2021-36369",
      "aliases": [
        "CVE-2021-36369"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/mkj/dropbear",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "d852d69b50187dd81d424846e7dc677ec57e2d4f"
                },
                {
                  "fixed": "b8669b063bd2fc1906a13fb4b50c8b4697bf49ce"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:dropbear_ssh_project:dropbear_ssh:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "2020.81"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "b8669b063bd2fc1906a13fb4b50c8b4697bf49ce"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "DROPBEAR_2022.82"
                  }
                ]
              }
            }
          ],
          "versions": [
            "DROPBEAR_2020.81",
            "DROPBEAR_2020.80",
            "DROPBEAR_2020.79",
            "DROPBEAR_2019.78",
            "DROPBEAR_2019.77",
            "DROPBEAR_2018.76",
            "DROPBEAR_2017.75",
            "DROPBEAR_2016.74",
            "DROPBEAR_2016.73",
            "DROPBEAR_2015.71",
            "DROPBEAR_2015.70",
            "DROPBEAR_2015.69",
            "DROPBEAR_2015.68",
            "DROPBEAR_2015.67",
            "DROPBEAR_2014.66",
            "DROPBEAR_2014.65",
            "DROPBEAR_2014.64",
            "DROPBEAR_2014.63",
            "DROPBEAR_2013.62",
            "DROPBEAR_2013.61test",
            "DROPBEAR_2013.60",
            "DROPBEAR_2013.59",
            "DROPBEAR_2013.58",
            "DROPBEAR_2013.57",
            "DROPBEAR_2013.56",
            "DROPBEAR_2012.55",
            "DROPBEAR_2011.54",
            "DROPBEAR_0.53.1",
            "DROPBEAR_0.53",
            "DROPBEAR_0.51",
            "DROPBEAR_0.50",
            "DROPBEAR_0.49",
            "DROPBEAR_0.48",
            "libtomcrypt-1.05"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-36369.json"
          }
        }
      ],
      "modified": "2026-10-20T10:53:50.703206098Z",
      "provider": "osv",
      "references": [
        "https://github.com/mkj/dropbear/pull/128",
        "https://github.com/mkj/dropbear/releases",
        "https://github.com/mkj/dropbear/releases/tag/DROPBEAR_2022.82",
        "https://lists.debian.org/debian-lts-announce/2022/11/msg00015.html"
      ],
      "provider_metadata": {
        "unresolved_ranges": [
          {
            "cpes": [
              "cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*"
            ],
            "vendor_product": "debian:debian_linux",
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "10.0"
                  },
                  {
                    "last_affected": "10.0"
                  }
                ],
                "source": "CPE_STRING"
              }
            ]
          }
        ]
      }
    },
    "related_cves": [
      {
        "value": "CVE-2021-36369",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 384686,
  "published_at": "2022-10-12T21:15:09.493+00:00"
}