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Fencer Vulns
high 7.1

CVE-2026-55700 json

pnpm: stage download writes outside destination via manifest version traversal

published 2026-06-25 4 mo ago modified 2026-06-29 4 mo ago also GHSA-v23m-ccfg-pq9h , EUVD-2026-39487

cvss
7.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 36%
public exploits
0
none known

Summary

pnpm is a package manager. From 11.3.0 until 11.5.3, `pnpm stage download` derived a local filename from registry-controlled package name and version fields. A crafted manifest could escape the selected download directory and overwrite another reachable file. The merged fix validates both fields, derives one safe filename, and verifies the final destination before writing. This vulnerability is fixed in 11.5.3.

Patch / fix

  • npm pnpm 11.5.3
  • pnpm pnpm 11.5.3

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-2026-55700 updated cvss 7.1

pnpm: pnpm: Unauthorized file modification via crafted package manifest

  • Red Hat AMQ Broker 7 pnpm
    not affected: vulnerable code not present
  • Red Hat Build of Keycloak pnpm
    not affected: component not present
  • Red Hat JBoss Enterprise Application Platform 8 pnpm Red Hat JBoss Enterprise Application Platform Expansion Pack pnpm
    not affected: vulnerable code not present

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
none
Automatable
no
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.42% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/pnpm/pnpm/security/advisories/GHSA-v23m-ccfg-pq9h referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L
GitHub 3.1 7.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L

Affected packages

ecosystem package affected fixed in
npm pnpm
>=11.3.0, <11.5.3
11.5.3

Affected products

  • pnpm pnpm

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory
  • CWE-73 External Control of File Name or Path

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.