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High, CVSS 7.5amended

pnpm: Manifest identity spoof satisfies allowBuilds and runs attacker lifecycle

CVE-2026-55487GHSA-5wx6-mg75-v57r

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (pnpm 11.5.3, 10.34.2), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

  • npm pnpm

    Affected
    < 10.34.2>= 11.0.0, < 11.5.3
    Fixed in
    10.34.2, 11.5.3

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
7.5 · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS
  • CVE-2026-55487: 0.18% estimated exploitation activity in the next 30 days; percentile 7.72 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Summary Keep build approval for opaque dependency sources byte-exact for GHSA-5wx6-mg75-v57r / CAND-PNPM-123. Merged upstream commit bf1b731ee6 fixed the original name-only approval bypass by making build policy consume the resolved dependency identity. One collision remained: 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. Security boundary - Registry dependency identities still normalize legitimate peer suffixes and retain patch hashes. - Git, URL, tarball, file, directory, and otherwise opaque identities must match the complete resolved locator byte for byte. - Explicit denials use the same normalization as approvals. - Ignored-build output preserves the exact opaque identity, so the key pnpm asks a user to approve is the key policy later checks. - TypeScript pnpm and…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 2 · amended ·

    Amended from ghsa record GHSA-5wx6-mg75-v57r

  2. Revision 1 · created ·

    Published from osv record GHSA-5wx6-mg75-v57r

Agent brief

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# Patch Next advisory brief: CVE-2026-55487

Advisory: pnpm: Manifest identity spoof satisfies allowBuilds and runs attacker lifecycle
IDs: CVE-2026-55487, GHSA-5wx6-mg75-v57r
Record: https://patchnext.com/advisories/cve-2026-55487 (revision 2, source checked 26 Oct 2026, 12:56 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: pnpm 11.5.3, 10.34.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm pnpm: affected < 10.34.2; >= 11.0.0, < 11.5.3; fixed in 10.34.2, 11.5.3

## Suggested inspection (read-only)
- `npm ls pnpm --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on pnpm.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-5wx6-mg75-v57r (OSV record GHSA-5wx6-mg75-v57r lists affected ranges: npm pnpm >=0 =11.0.0 <11.5.3 (fixed))
- Verified: https://github.com/advisories/GHSA-5wx6-mg75-v57r (GitHub-reviewed advisory GHSA-5wx6-mg75-v57r lists affected ranges: npm pnpm >=0 =11.0.0 <11.5.3)

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