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Fencer Intel
high 7.5

CVE-2026-55487 json

pnpm: manifest identity spoof satisfies allowBuilds and runs attacker lifecycle

published 4mo ago modified 4mo ago also EUVD-2026-39481 , GHSA-5wx6-mg75-v57r

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

pnpm is a package manager. Prior to 10.34.2 and 11.5.3, the generic peer-suffix normalizer also stripped parenthesized text from git, URL, tarball, file, and other opaque locators. Approval for one source string could therefore authorize a different attacker-controlled source whose locator normalized to the same value. This vulnerability is fixed in 10.34.2 and 11.5.3.

Patch / fix

  • npm pnpm 10.34.2, 11.5.3
  • pnpm pnpm 10.34.2, 11.5.3

Is CVE-2026-55487 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

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-2026-55487 updated cvss 7.5

pnpm: pnpm: Supply chain compromise via manipulated package source strings

  • 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
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
4mo ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/pnpm/pnpm/security/advisories/GHSA-5wx6-mg75-v57r referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
npm pnpm
<10.34.2
>=11.0.0, <11.5.3
10.34.2
11.5.3

Affected products

  • pnpm pnpm

Classification

Weakness
  • CWE-346 Origin Validation Error
  • CWE-693 Protection Mechanism Failure
  • CWE-829 Inclusion of Functionality from Untrusted Control Sphere

References

Sources

Fencer Intel 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.

The maintainers of pnpm/pnpm published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.