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Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVE-2026-23888

Medium
6.5/10

Summary

pnpm is a package manager. In pnpm versions through 10.28.0 and 11.x through 11.0.0-alpha.3 and @pnpm/fetching.binary-fetcher versions through 1005.0.1, a Path Traversal vulnerability in pnpm's binary fetcher allows malicious packages to write files outside the intended extraction directory. The vulnerability has two attack vectors: (1) Malicious ZIP entries containing `../` or absolute paths that escape the extraction root via AdmZip's `extractAllTo`, and (2) The `BinaryResolution.prefix` field is concatenated into the extraction path without validation, allowing a crafted prefix like `../../evil` to redirect extracted files outside `targetDir`. The issue impacts all pnpm users who install packages with binary assets, users who configure custom Node.js binary locations and CI/CD pipelines that auto-install binary dependencies. It can lead to overwriting config files, scripts, or other sensitive files leading to RCE. Version 10.28.1 of pnpm and 1005.0.2 of @pnpm/fetching.binary-fetcher contains a patch for this issue.

  • LOW
  • NETWORK
  • HIGH
  • UNCHANGED
  • REQUIRED
  • NONE
  • NONE
  • NONE

CWE-22 - Path Traversal

Path traversal (or directory traversal), is a vulnerability that allows malicious users to traverse the server's root directory, gaining access to arbitrary files and folders such as application code & data, back-end credentials, and sensitive operating system files. In the worst-case scenario, an attacker could potentially execute arbitrary files on the server, resulting in a denial of service attack. Such an exploit may severely impact the integrity, confidentiality, and availability of an application.

References

Advisory Timeline

  • Published