CVE-2026-50016: pnpm: Transitive dependency alias path traversal allows project path override via symlink replacement

pnpm allows a transitive dependency alias from registry package metadata to contain path traversal segments. During install, pnpm later uses that alias as a filesystem path when linking dependency nodes. As a result, a registry package can cause pnpm install - ignore-scripts to replace paths in the current project with symlinks to attacker-controlled dependency package directories.

.git/hooks is only one useful target. The same primitive can replace other project-local paths that are consumed by later tools, for example:

• .husky or .githooks for Git hook dispatchers
• scripts/, tools/, bin/, or tests/ for project scripts and CI commands
• .github/actions/<name> for local GitHub Actions used later in the workflow
• dist/ or other publish/build output directories before pnpm pack or pnpm publish
• node_modules/.bin or undeclared node_modules/<name> paths used by later command or module resolution

Targets that are regular files can also be replaced with symlinks to a package directory, but those cases are usually denial of service. Directory targets are more useful because many developer tools execute or load files from those directories after installation.

This was reproduced with pnpm@11.2.1.