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Fencer Vulns
medium 6.5

CVE-2026-23889 json

pnpm has Windows-specific tarball Path Traversal

published 2026-01-26 9 mo ago modified 2026-06-17 4 mo ago also GHSA-6x96-7vc8-cm3p , EUVD-2026-4657

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 41%
public exploits
0
none known

Summary

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.

Patch / fix

  • npm pnpm 10.28.1
  • pnpm pnpm 10.28.1
  • pnpm Alpine 3.23 10.33.4-r0

alpine advisories ALPINE-CVE-2026-23889

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-23889 updated cvss 6.5

pnpm: pnpm: Arbitrary file write via path traversal on Windows

  • Red Hat JBoss Enterprise Application Platform 8 org.keycloak-keycloak-parent Red Hat JBoss Enterprise Application Platform Expansion Pack org.keycloak-keycloak-parent
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
9 mo ago

Exploit prediction

0.48% chance of exploitation in the next 30 days, higher than 41% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/pnpm/pnpm/security/advisories/GHSA-6x96-7vc8-cm3p referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
GitHub 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
npm pnpm
<10.28.1
10.28.1

Affected products

  • pnpm pnpm

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.