CVE-2026-23888: pnpm path traversal in binary extraction (Zip Slip)

CVE-2026-23888 · Severity: low · CVSS 3.1 · Published 2026-01-26

pnpm is a package manager used by developers to install and manage software dependencies. When pnpm downloads and extracts binary dependencies for Node.js or other tools, a flaw allows malicious packages to write files outside the intended directory by exploiting path traversal techniques. An attacker could overwrite critical configuration files or scripts, potentially gaining the ability to execute arbitrary code on affected systems.

Technologies: pnpm (npm). Vendors: npm.

Quick answers

Is CVE-2026-23888 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-23888 being exploited in the wild.
How severe is CVE-2026-23888?
Low severity, with a CVSS score of 3.1, published 26 January 2026.
Which products and versions are affected?
pnpm (npm) SEMVER:introduced=0,fixed=10.28.1.
Is there a fix for CVE-2026-23888?
Yes. pnpm (npm): upgrade to 10.28.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-23888 attacked?
It is attacked over the network.
Am I affected by CVE-2026-23888?
Check whether you run pnpm (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • pnpm (npm): upgrade to 10.28.1 or later
    npm install pnpm@10.28.1

Technical details

The vulnerability is a path traversal flaw (CWE-22, "Zip Slip") in pnpm's binary fetching logic. The root cause is improper validation of ZIP entry paths during extraction: the AdmZip library's extractAllTo method does not sanitize paths containing ../ sequences or absolute paths, and the BinaryResolution.prefix field is concatenated directly into the extraction path without validation. An attacker can craft a malicious package with ZIP entries containing traversal sequences (e.g., ../../../.npmrc) or provide a malicious prefix value in a package's resolution metadata to redirect file writes outside the target directory. The attack requires user interaction (installing a package) and network access (from a remote source or compromised registry). Successful exploitation allows overwriting configuration files, scripts, or binaries, potentially leading to remote code execution. The vulnerability affects pnpm versions prior to 10.28.1, which includes a fix that validates and sanitizes extraction paths.

Affected products

  • pnpm pnpm < 10.28.1

Identifiers

  • CVE-2026-23888
  • GHSA-6pfh-p556-v868

Timeline

  • 2026-01-26: disclosed: Advisory published
  • 2026-01-26: patched: Fixed in pnpm v10.28.1

References

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