CVE-2026-21439Public exploit

Misleading terminal output via unescaped scan labels

Published Jan 5, 2026 · Updated Jan 5, 2026

Terminal injection in badkeys 0.0.15 and earlier allows attackers to falsify CLI output through crafted key data or filenames. The CLI interpolates unescaped DKIM key types, SSH key comments, filenames, and other scan labels into terminal messages, so control characters are interpreted instead of displayed as data. An operator must scan attacker-influenced input in an affected mode; the demonstrated consequence is misleading terminal output, not code execution or service interruption.

CVSS severity5.3
Medium
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Terminal injection in badkeys 0.0.15 and earlier allows attackers to falsify CLI output through crafted key data or filenames. The CLI interpolates unescaped DKIM key types, SSH key comments, filenames, and other scan labels into terminal messages, so control characters are interpreted instead of displayed as data. An operator must scan attacker-influenced input in an affected mode; the demonstrated consequence is misleading terminal output, not code execution or service interruption.

The record

CVE
CVE-2026-21439
Published
Jan 5, 2026
Updated
Jan 5, 2026
Vendor
badkeys
Product
badkeys
Classifications
CWE-150, T1036
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 5, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.0.16

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

badkeys · badkeysversion=< 0.0.16

Published CVSS scores

2.0GitHub, Inc.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
5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-150Improper Neutralization of Escape, Meta, or Control Sequences
T1036Masquerading

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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