{
  "cveId": "CVE-2021-32749",
  "url": "https://patchblox.com/security/cve/CVE-2021-32749",
  "summary": "CVE-2021-32749 is fixed in fail2ban on 1 platform, first by fail2ban 0.10.2-2ubuntu0.1~esm1, released July 16, 2021. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "fail2ban: fail2ban is a daemon to ban hosts that cause multiple authentication errors",
  "description": "fail2ban is a daemon to ban hosts that cause multiple authentication errors. In versions 0.9.7 and prior, 0.10.0 through 0.10.6, and 0.11.0 through 0.11.2, there is a vulnerability that leads to possible remote code execution in the mailing action mail-whois. Command \u0060mail\u0060 from mailutils package used in mail actions like \u0060mail-whois\u0060 can execute command if unescaped sequences (\u0060\\n~\u0060) are available in \u0022foreign\u0022 input (for instance in whois output). To exploit the vulnerability, an attacker would need to insert malicious characters into the response sent by the whois server, either via a MITM attack or by taking over a whois server. The issue is patched in versions 0.10.7 and 0.11.3. As a workaround, one may avoid the usage of action \u0060mail-whois\u0060 or patch the vulnerability manually.",
  "published": "2021-07-16T11:15:00Z",
  "severity": "Medium",
  "epss": 0.03428,
  "epssPercentile": 0.8901,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "fail2ban",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "0.10.2-2ubuntu0.1~esm1",
      "fix": "fail2ban 0.10.2-2ubuntu0.1~esm1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-fail2ban-0.10.2-2ubuntu0.1-esm1",
      "released": "2021-07-16T11:15:00Z"
    },
    {
      "platform": "linux",
      "product": "fail2ban",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "0.11.1-1ubuntu0.1~esm1",
      "fix": "fail2ban 0.11.1-1ubuntu0.1~esm1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-fail2ban-0.11.1-1ubuntu0.1-esm1",
      "released": "2021-07-16T11:15:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T19:12:23Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}