Path Traversal in Microsoft Windows
CVE-2026-23889
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.
Vulnerability class: Path Traversal (Directory Traversal)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.005 (40.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 40th percentile — 40.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.001
Affected products
- Microsoft Windows
- Pnpm — versions < 10.28.1
Weakness classification (CWE)
References
- github.com/pnpm/pnpm/security/advisories/GHSA-6x96-7vc8-cm3p (Exploit, Vendor Advisory)
- github.com/pnpm/pnpm/commit/6ca07ffbe6fc0e8b8cdc968f228903ba0886f7c0 (Patch)
- github.com/pnpm/pnpm/releases/tag/v10.28.1 (Patch)
Frequently asked questions
- What is CVE-2026-23889?
- CVE-2026-23889 is a medium-severity vulnerability in Microsoft Windows, classified under Path Traversal. CVSS score: 6.5/10. Published 2026-01-26.
- How severe is CVE-2026-23889?
- Medium severity. CVSS v3 base score is 6.5 out of 10.