GitHub tightens npm publishing process after vulnerability exposed more than 1,500 packages to hijacking risk

GitHub has tightened the npm trusted publishing mechanism: newly created trusted publishing configurations now expire if they do not complete their first successful publish within 48 hours, in response to a vulnerability discovered by Bloom Security. The vulnerability, named SlugFest, allows attackers to claim repository slugs whose maintainers have renamed, transferred, or deleted them, inheriting their trust relationships and thereby publishing malicious versions under legitimate package names. The researchers found more than 1,500 affected packages with a combined total of more than 10 million downloads, and reported the issue to GitHub on June 6, 2026. npm also now rejects tokens from issue_comment events. Bloom Security noted that AI agents on developers' machines resolve dependencies on their own, tend to take the latest version, and rarely check the source, which can cause malicious versions to be pulled and run without human intervention. The researchers recommend that maintainers audit trusted publishing bindings and delete old bindings after renaming, transferring, or deleting a repository.