pnpm, a JavaScript package manager, had a flaw that allowed an integrity check bypass when installing in non‑frozen mode. If a package is locked with a specific integrity hash, a later registry response that contains different metadata and tarball content will initially trigger an integrity mismatch. However, pnpm automatically performs a resolution repair, accepts the new integrity, rewrites the lockfile, installs the new content, and exits normally. This means the lockfile integrity check is not a hard stop, permitting a malicious package to replace a trusted one without detection. The vulnerability can lead to supply‑chain compromise and potentially arbitrary code execution.

pnpm version 10.33.x and earlier as well as pnpm 11.x versions prior to 11.4.0 are affected. Any installation that uses non‑frozen mode and relies on the lockfile integrity check is vulnerable.

The vulnerability has a CVSS score of 6.8, indicating a moderate severity. The EPSS score is not available, and the vulnerability is not listed in the CISA KEV catalog, suggesting no widespread exploitation yet. The flaw requires a registry that can supply altered package metadata and tarball content, so an attacker controlling or compromising a registry can exploit it. Because the lockfile is automatically updated, the attack would be stealthy unless the attacker’s compromise is detected through other means.