GHSA-wjpc-4f29-83h3 — low GitHub Advisory (CVE-2026-21439) in pip/badkeys

Description

Impact

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.

Patches

This has been fixed with the following commits:
https://github.com/badkeys/badkeys/commit/de631f69f040974bb5fb442cdab9a1d904c64087
https://github.com/badkeys/badkeys/commit/635a2f3b1b50a895d8b09ec8629efc06189f349a

All users should upgrade badkeys to version 0.0.16.

Resources

https://github.com/badkeys/badkeys/issues/40

Basic information

Type: reviewed
Severity: low
Advisory on GitHub: Open advisory ↗
Repository advisory: Open repository advisory ↗
Source code: Browse source ↗
Published (advisory): 2026-01-05 19:42:12 UTC
Updated: 2026-01-06 16:07:16 UTC
GitHub reviewed: 2026-01-05 19:42:12 UTC
NVD published: 2026-01-05

Score	Percentile
0.01%	2.60%

CVSS Scores

Base score	Version	Severity	Vector
2.0	4.0	—	`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` Click to expand Attack vector (AV:L) Attacker needs local access on the target system. Attack complexity (AC:L) Exploitation conditions are straightforward and stable. Attack requirements (AT:N) No additional preconditions are required beyond normal reachability. Privileges required (PR:N) No privileges are required. User interaction (UI:N) No user interaction is required. Vulnerable system confidentiality impact (VC:N) No confidentiality impact on the vulnerable system. Vulnerable system integrity impact (VI:L) Limited integrity impact on the vulnerable system. Vulnerable system availability impact (VA:N) No availability impact on the vulnerable system. Subsequent system confidentiality impact (SC:N) No confidentiality impact on subsequent systems. Subsequent system integrity impact (SI:N) No integrity impact on subsequent systems. Subsequent system availability impact (SA:N) No availability impact on subsequent systems. Exploit maturity (threat) (E:P) Proof-of-concept: public PoC exists; no reported exploitation and no known simplification tools.

Identifiers

Type	Value
GHSA	GHSA-wjpc-4f29-83h3 ↗
CVE	CVE-2026-21439 ↗

CWEs

CWE id	Name
CWE-150	Improper Neutralization of Escape, Meta, or Control Sequences

Credits

hannob (finder)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem	Package	Vulnerable range	First patched	Vulnerable functions
pip	badkeys	<= 0.0.15	0.0.16	—

badkeys vulnerable to ASCII control character injection on console via malformed input