CVE-2026-21439 badkeys vulnerable to ASCII control character injection on console via malformed input
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-21439?
CVE-2026-21439 is a low-severity vulnerability in badkeys, published on 5 Jan 2026.
Official 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.
Weakness: CWE-150
Which versions are affected by CVE-2026-21439?
3 open source packages ship an affected version, including badkeys. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
badkeys PyPI | All versions | 0.0.16 |
badkeys PyPI | All versions | 0.0.16 |
badkeys PyPI | All versions | 0.0.16 |
Products include Badkeys Badkeys.
How do I fix CVE-2026-21439?
Upgrade badkeys to 0.0.16 or later.
Is CVE-2026-21439 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-21439 exists.
Sources
Also known as GHSA-wjpc-4f29-83h3, PYSEC-2026-1212.