pnpm, a widely used package manager, incorrectly associates a user’s unscoped npm authentication token with a registry specified in a repository’s local .npmrc file. In releases before 10.34.0 and 11.4.0 the token is transmitted as an Authorization header to the registry chosen by that .npmrc, exposing the token to the registry host. This can enable an attacker to impersonate the user, access private packages, or conduct further malicious activity. The vulnerability involves credential storage (CWE‑201).

pnpm 10.x versions earlier than 10.34.0 and 11.x versions earlier than 11.4.0 are vulnerable. The issue occurs when a repository’s .npmrc sets the registry property without providing an explicit authentication entry.

The CVSS score of 6.9 indicates moderate severity. The EPSS score of < 1% denotes a very low exploitation probability, and the vulnerability is not listed in CISA KEV, which suggests the risk to unpatched environments is currently limited. Based on the most likely attack vector, a repository maintainer or collaborator could place a malicious .npmrc file in a project, configuring the registry to point to an attacker’s server, which results in the token being sent as an Authorization header to that remote registry.