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Vulnerabilities

Security fix · CVE-2026-21439

badkeys is a tool and library for checking cryptographic public keys for known vulnerabilities.

Published Jan 5, 2026 · catalog updated Jan 6, 2026 · badkeys is a tool

Last checked Nov 3, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-21439. EPSS is 0.33%. Act only if a listed version of badkeys is a tool is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (badkeys is a tool).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Low2.0
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.33%
Remediation
Version ranges on file
Affected products
vendor badkeys badkeys < 0.0.16

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor badkeys badkeys < 0.0.16< 0.0.16

How to fix CVE-2026-21439

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-21439. EPSS is 0.33%. Act only if a listed version of badkeys is a tool is installed.

Which versions are affected?

Compare what you have installed with badkeys badkeys < 0.0.16 < 0.0.16. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.33%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jan 5, 2026 · EUVD

    Detected

    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 f

  2. Jan 6, 2026 · EUVD

    Updated

    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 f

Sources

  • CVE.orgVulnerability recordCVE-2026-21439

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-21439

    30-day exploitation probability 0.33%

    first.org
  • EUVDVulnerability recordEUVD-2026-0823

    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 bad

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Nov 3, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 3, 2026
  • CVE.orgOct 31, 2026
  • EUVDOct 31, 2026