fail2ban — security advisory

{
  "id": "c14a2aba3a0d1642d2f3e7995abcbcd41afd7d97470766235576a776d398fad8",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2007-4321",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2007-4321",
    "summary": "fail2ban 0.8 and earlier does not properly parse sshd log files, which allows remote attackers to add arbitrary hosts to the /etc/hosts.deny file and cause a denial of service by adding arbitrary IP addresses to the sshd log file, as demonstrated by logging in via ssh with a client protocol version identification containing an IP address string, a different vector than CVE-2006-6302.",
    "evidence": "osv:DEBIAN-CVE-2007-4321",
    "products": [
      {
        "name": {
          "value": "fail2ban",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.8.0-4",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "fail2ban",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.8.0-4",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "fail2ban",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.8.0-4",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "DEBIAN-CVE-2007-4321",
      "aliases": [
        "DEBIAN-CVE-2007-4321"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "0.8.0-4"
                }
              ]
            }
          ],
          "package": {
            "name": "fail2ban",
            "purl": "pkg:deb/debian/fail2ban?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2007-4321.json"
          },
          "ecosystem_specific": {
            "urgency": "medium"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "0.8.0-4"
                }
              ]
            }
          ],
          "package": {
            "name": "fail2ban",
            "purl": "pkg:deb/debian/fail2ban?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2007-4321.json"
          },
          "ecosystem_specific": {
            "urgency": "medium"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "0.8.0-4"
                }
              ]
            }
          ],
          "package": {
            "name": "fail2ban",
            "purl": "pkg:deb/debian/fail2ban?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2007-4321.json"
          },
          "ecosystem_specific": {
            "urgency": "medium"
          }
        }
      ],
      "modified": "2026-10-21T17:47:31.880458336Z",
      "provider": "osv",
      "upstream": [
        "CVE-2007-4321"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2007-4321"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2007-4321",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 398251,
  "published_at": "2007-08-14T00:17:00+00:00"
}