CVE-2026-21439

Name: CVE-2026-21439
Creator: NVD / NIST
Published: 2026-01-06T00:15:49.027+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

LOWCVSS 2/10EPSS 0.30%

Last modified Jun 17, 2026

CVE-2026-21439 is a low-severity vulnerability rated 2/10 on the CVSS scale. 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. EPSS estimates a 0.30% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

5.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS 4.0

2/10

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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.30%

21.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-150

Affected Software

Vendor	Product	Versions
Badkeys	Badkeys	< 0.0.16

References

https://github.com/badkeys/badkeys/commit/635a2f3b1b50a895d8b09ec8629efc06189f349aPatch
https://github.com/badkeys/badkeys/commit/de631f69f040974bb5fb442cdab9a1d904c64087Patch
https://github.com/badkeys/badkeys/issues/40Exploit, Issue Tracking, Third Party Advisory
https://github.com/badkeys/badkeys/security/advisories/GHSA-wjpc-4f29-83h3Third Party Advisory
https://github.com/badkeys/badkeys/issues/40Exploit, Issue Tracking, Third Party Advisory

Timeline

Published: Jan 6, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-21439?

How severe is CVE-2026-21439?

CVE-2026-21439 has a CVSS score of 2/10 (LOW severity). The EPSS model estimates a 0.30% probability of exploitation in the next 30 days.

How do I fix CVE-2026-21439?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-21439?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST