BREW-BADKEYS-CVE-2026-21439 (CVE-2026-21439)

Vulnerability from osv_homebrew – Published: 2026-08-13 16:37 – Updated: 2026-09-30 09:11 – Source website
VLAI
Summary
badkeys vulnerable to ASCII control character injection on console via malformed input
Details

badkeys is a tool and library for checking cryptographic public keys for known vulnerabilities. In versions 0.0.15 and below, an attacker may inject content with ASCII control characters like vertical tabs, ANSI escape sequences, etc., that can create misleading output of the badkeys command-line tool. This impacts scanning DKIM keys (both --dkim and --dkim-dns), SSH keys (--ssh-lines mode), and filenames in various modes. This issue is fixed in version 0.0.16.

Severity
2.0 (Low)
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": "bump",
        "range_state": "fixed",
        "upstream_fixed_in": "0.0.16"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "badkeys",
        "purl": "pkg:brew/badkeys"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.0.19"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "git",
    "upstream_evidence": [
      {
        "ecosystem": "GIT",
        "key": "https://github.com/badkeys/badkeys",
        "name": "https://github.com/badkeys/badkeys",
        "strategy": "git",
        "subject_version": "0.0.21"
      },
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/badkeys@0.0.21",
        "name": "badkeys",
        "strategy": "registry",
        "subject_version": "0.0.21"
      }
    ]
  },
  "details": "badkeys is a tool and library for checking cryptographic public keys for known vulnerabilities. In versions 0.0.15 and below, an attacker may inject content with ASCII control characters like vertical tabs, ANSI escape sequences, etc., that can create misleading output of the badkeys command-line tool. This impacts scanning DKIM keys (both --dkim and --dkim-dns), SSH keys (--ssh-lines mode), and filenames in various modes. This issue is fixed in version 0.0.16.",
  "id": "BREW-badkeys-CVE-2026-21439",
  "modified": "2026-09-30T09:11:56Z",
  "published": "2026-08-13T16:37:04Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/21xxx/CVE-2026-21439.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/badkeys/badkeys/security/advisories/GHSA-wjpc-4f29-83h3"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-21439"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/badkeys/badkeys/issues/40"
    },
    {
      "type": "FIX",
      "url": "https://github.com/badkeys/badkeys/commit/635a2f3b1b50a895d8b09ec8629efc06189f349a"
    },
    {
      "type": "FIX",
      "url": "https://github.com/badkeys/badkeys/commit/de631f69f040974bb5fb442cdab9a1d904c64087"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P",
      "type": "CVSS_V4"
    }
  ],
  "summary": "badkeys vulnerable to ASCII control character injection on console via malformed input",
  "upstream": [
    "CVE-2026-21439",
    "GHSA-wjpc-4f29-83h3",
    "PYSEC-2026-1212"
  ]
}



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