# CVE-2026-55487: pnpm build policy bypass via opaque locator normalization spoofing

Source: https://junglewise.ai/threats/cve-2026-55487-pnpm-build-policy-bypass-via-opaque-locator-normalization  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-25. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-55487 · Severity: high · CVSS 7.5 · Published 2026-06-25

pnpm is a popular JavaScript package manager that supports build approval policies for third-party dependencies. This vulnerability allows attackers to bypass build approval controls by spoofing package identities—an attacker can get approval for one package source and then run builds from a different attacker-controlled source. An exploit requires user interaction (manually approving a build) but could lead to arbitrary code execution during package installation.

Technologies: [pnpm (npm)](https://junglewise.ai/threats/technologies/pnpm). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2026-55487 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-55487 being exploited in the wild.

**How severe is CVE-2026-55487?** High severity, with a CVSS score of 7.5, published 25 June 2026.

**Which products and versions are affected?** pnpm (npm) SEMVER:introduced=0,fixed=10.34.2.

**Is there a fix for CVE-2026-55487?** Yes. pnpm (npm): upgrade to 10.34.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-55487 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-55487?** Check whether you run pnpm (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- pnpm (npm): upgrade to 10.34.2 or later

  ```sh
  npm install pnpm@10.34.2
  ```


## Technical details

The vulnerability exists in pnpm's build approval policy implementation. The affected code applies generic peer-suffix normalization (stripping parenthesized text) to both registry and opaque (git, URL, tarball, file, directory) dependency locators. This normalization allows different source strings to collide: for example, both `foo@https://host/pkg.tgz` and `foo@https://host/pkg.tgz(evil)` normalize to the same value after parenthesized text is removed, allowing an attacker to construct a malicious locator that matches an approved source. The vulnerability class is CWE-346 (Origin Validation Error) and requires user interaction to approve a build. The patch (versions 10.34.2 and 11.5.3+) enforces byte-exact matching for opaque identities while retaining normalized matching for legitimate registry packages, preventing collision-based spoofing.

## Affected products

- pnpm pnpm <10.34.2, >=11.0.0 <11.5.3

## Identifiers

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

## Timeline

- 2026-06-26: disclosed: GHSA-5wx6-mg75-v57r published on OSV
- 2026-06-10: patched: Patch commit bf1b731ee6 merged to fix the original name-only approval bypass
- 2026-06-26: other: Final patch released in pnpm v10.34.2 and v11.5.3 addressing all three collision forms

## References

- [https://github.com/pnpm/pnpm/security/advisories/GHSA-5wx6-mg75-v57r](https://github.com/pnpm/pnpm/security/advisories/GHSA-5wx6-mg75-v57r)
- [https://github.com/pnpm/pnpm/commit/bf1b731ee6c0ea98709e671ff0f46bf654480ab8](https://github.com/pnpm/pnpm/commit/bf1b731ee6c0ea98709e671ff0f46bf654480ab8)
- [https://github.com/pnpm/pnpm](https://github.com/pnpm/pnpm)
- [https://github.com/pnpm/pnpm/releases/tag/v10.34.2](https://github.com/pnpm/pnpm/releases/tag/v10.34.2)
- [https://github.com/pnpm/pnpm/releases/tag/v11.5.3](https://github.com/pnpm/pnpm/releases/tag/v11.5.3)

## Related threats

- [pnpm environment secret exfiltration via proxy settings in workspace manifest](https://junglewise.ai/threats/pnpm-environment-secret-exfiltration-via-proxy-settings-in-workspace-f6626cca)
- [pnpm pacquet path traversal in lockfile dependency symlinks](https://junglewise.ai/threats/pnpm-pacquet-path-traversal-in-lockfile-dependency-symlinks-dc3f81d1)
- [pnpm tarball dependency manifest name path traversal arbitrary file write](https://junglewise.ai/threats/cve-2026-82393-pnpm-tarball-dependency-manifest-name-path-traversal-arbitrary)
- [pnpm virtual store linker path traversal via unvalidated depPath](https://junglewise.ai/threats/cve-2026-82392-pnpm-virtual-store-linker-path-traversal-via-unvalidated-deppath)
- [pnpm path traversal via crafted lockfile alias](https://junglewise.ai/threats/cve-2026-59196-pnpm-path-traversal-via-crafted-lockfile-alias)