Affected Systems
npm packages using trusted publishing with GitHub Actions where the linked repository slug (owner/repository) has never completed a successful publish, or where repositories have been renamed, transferred, or deleted. Over 1,500 packages with 10+ million collective downloads identified as vulnerable.
Exploitation Status
No active exploitation reported. Vulnerability disclosed to GitHub on June 6, 2026. GitHub implemented mitigations (48-hour expiration for unvalidated configurations) before public disclosure. Proof-of-concept demonstrated by Bloom Security researchers.
Business Impact
Attackers could publish malicious versions of legitimate npm packages without credential theft by reclaiming abandoned GitHub repository slugs. Malicious packages inherit reputation, download counts, and dependency relationships, enabling supply chain attacks. Risk amplified by AI coding agents that auto-resolve dependencies and pull latest versions without human review. GitHub's 48-hour validation window and rejection of tokens from issue_comment events now limit exposure window.
Urgency
🟡 Within a week
Recommended Actions
- Audit all npm trusted publisher configurations immediately: verify each listed repository slug still resolves to a repository under your control via npm package settings.
- Delete and recreate trusted publisher bindings for any repositories that have been renamed, transferred, or deleted to bind them to current immutable repository IDs.
- Implement monitoring for unexpected npm publish events via npm audit logs and GitHub Actions workflow notifications.
- Establish policy to delete npm trusted publisher bindings whenever a GitHub repository is renamed, transferred, or deleted.
- For packages not yet published via trusted publishing, complete first publish within 48 hours of configuration creation to validate and lock the binding to the immutable repository ID.