Security advisory

{
  "id": "090e0e759dba58f3d88fcccd07d8caca69755729bcf1c51b65bd9a3390754225",
  "url": "https://osv.dev/vulnerability/CVE-2021-44512",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-44512",
    "summary": "World-writable permissions on the /tmp/tmate/sessions directory in tmate-ssh-server 2.3.0 allow a local attacker to compromise the integrity of session handling, or obtain the read-write session ID from a read-only session symlink in this directory.",
    "evidence": "osv:CVE-2021-44512",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2021-44512",
      "aliases": [
        "CVE-2021-44512"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/tmate-io/tmate-ssh-server",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "8fc519a62512bbfedefc7cee55511f3063f2958d"
                },
                {
                  "fixed": "1c020d1f5ca462f5b150b46a027aaa1bbe3c9596"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:tmate:tmate-ssh-server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "2.3.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "1c020d1f5ca462f5b150b46a027aaa1bbe3c9596"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "2.3.0",
            "base",
            "1.8",
            "to_copy"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-44512.json",
            "vanir_signatures": [
              {
                "id": "CVE-2021-44512-b4fa32fc",
                "digest": {
                  "length": 1691,
                  "function_hash": "316549956568796934807268776517522169863"
                },
                "source": "https://github.com/tmate-io/tmate-ssh-server/commit/1c020d1f5ca462f5b150b46a027aaa1bbe3c9596",
                "target": {
                  "file": "tmate-main.c",
                  "function": "main"
                },
                "deprecated": false,
                "signature_type": "Function",
                "signature_version": "v1"
              },
              {
                "id": "CVE-2021-44512-b5bc6fcf",
                "digest": {
                  "threshold": 0.9,
                  "line_hashes": [
                    "80207026068406672254999970398237947067",
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                    "310518699917455409064642457929409388070",
                    "176290184624510983014086540170709540683",
                    "152451022566174787559069177947798513311",
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                    "21004837053619300072504869666184033231",
                    "211129072721360576409360749973093728649",
                    "229693977904854031536266170358141525484",
                    "152841598158707753820788575096253228192"
                  ]
                },
                "source": "https://github.com/tmate-io/tmate-ssh-server/commit/1c020d1f5ca462f5b150b46a027aaa1bbe3c9596",
                "target": {
                  "file": "tmate-main.c"
                },
                "deprecated": false,
                "signature_type": "Line",
                "signature_version": "v1"
              }
            ],
            "vanir_signatures_modified": "2026-10-20T14:06:55Z"
          }
        }
      ],
      "modified": "2026-10-20T14:06:55.355359229Z",
      "provider": "osv",
      "references": [
        "https://www.openwall.com/lists/oss-security/2021/12/06/2",
        "https://github.com/tmate-io/tmate-ssh-server/commit/1c020d1f5ca462f5b150b46a027aaa1bbe3c9596"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-44512",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 388569,
  "published_at": "2021-12-07T03:15:07.16+00:00"
}