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Malicious package

markdownlint-rule-link-patternnpm

Advisory published Updated

markdownlint-rule-link-pattern is a confirmed malicious npm package (MAL-2026-2633) that steals credentials and exfiltrates sensitive data. Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in markdownlint-rule-link-pattern (npm)

MAL-2026-2633
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall markdownlint-rule-link-pattern

What this malware does

Malicious package due to data exfiltration via preinstall, test and preupdate scripts using wget to send user, path, and hostname to a remote server.

The package markdownlint-rule-link-pattern was found to contain malicious code.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

Malicious versions

all versions

Every published version of this package is considered malicious — remove it entirely.

Indicators of compromise (SHA-256)

b29e059ae96dd2d806ee28cddc7b1d0e5fa5b58708dc895f9f5bdb34cf300838
2c5ffad19a9d8a62d1ee2a266767e609ffeba74597b50248d751b28cdffae844

Detection & response playbook

Credential / info stealer

  1. Find it

    Search your lockfiles and build artifacts for markdownlint-rule-link-pattern (all published versions).

  2. If you installed it — respond

    markdownlint-rule-link-pattern is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.

  3. Did it already run?

    If markdownlint-rule-link-pattern was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Frequently asked questions

No. markdownlint-rule-link-pattern on npm has been identified as a malicious package (all published versions flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

GHSA-q3xp-j858-q9xf

References

Credits

  • Amazon Inspector · finder
  • SafeDep · finder

Detect & block this

O3 blocks markdownlint-rule-link-pattern-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Malware detection Runtime egress monitoring

Explore

All malware advisories How O3 detects malware Vulnerability database
markdownlint-rule-link-pattern (npm) malicious package — MAL-2026-2633 | O3 Security