CVE-2026-21439 json
badkeys vulnerable to ASCII control character injection on console via malformed input
published 2026-01-05 10 mo ago modified 2026-07-07 4 mo ago also GHSA-wjpc-4f29-83h3 , PYSEC-2026-1212 , EUVD-2026-0823
- cvss
- 5.3
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 26%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- pypi badkeys 0.0.16
- badkeys badkeys 0.0.16
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 10 mo ago
Exploit prediction
0.33% chance of exploitation in the next 30 days, higher than 26% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/badkeys/badkeys/issues/40 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 2.0 | 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 |
| CNA | 4.0 | 2.0 | 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/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 |
| NVD | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | badkeys | <0.0.16 |
0.0.16 |
Affected products
- badkeys badkeys
Classification
- Weakness
-
- CWE-150 Improper Neutralization of Escape, Meta, or Control Sequences
References
-
github.com
/badkeys/badkeys/commit/635a2f3b1b50a895d8b09ec8629efc06189f349a
web, patch
-
github.com
/badkeys/badkeys/commit/de631f69f040974bb5fb442cdab9a1d904c64087
web, patch
-
github.com
/badkeys/badkeys/issues/40
exploit, web, issue-tracking, third-party-advisory
-
github.com
/badkeys/badkeys/security/advisories/GHSA-wjpc-4f29-83h3
web, third-party-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-21439
advisory
-
github.com
/badkeys/badkeys
package
-
pypi.org
/project/badkeys
package
-
github.com
/advisories/GHSA-wjpc-4f29-83h3
advisory
Sources
- CVE List CVE-2026-21439
- GitHub Advisory GHSA-wjpc-4f29-83h3
- NVD CVE-2026-21439
- OSV PYSEC-2026-1212
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.