What is the CVSS score of CVE-2026-55700?

CVE-2026-55700 has a CVSS 3.1 base score of 7.1 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L. EPSS exploitation probability: 0.3%.

Which versions of pnpm are affected by CVE-2026-55700?

A path traversal vulnerability in pnpm versions 11.3.0-11.5.2 could allow attackers using compromised package registries to overwrite arbitrary files on developer machines and CI/CD systems.. A patch is available.

Is there a public PoC exploit available for CVE-2026-55700?

Yes, a public proof-of-concept exploit is available for CVE-2026-55700. Prioritise patching immediately. EPSS: 0.3%.

How to fix or mitigate CVE-2026-55700?

Within 24 hours: Audit systems and CI/CD pipelines using pnpm versions 11.3.0-11.5.2; document current pnpm version across development teams. Within 7 days: Upgrade all instances to pnpm version 11.5.3 or later and verify completion. Within 30 days: Implement package registry security policies restricting access to trusted registries only.

pnpm CVE-2026-55700

EUVD-2026-39487 HIGH

Path Traversal (CWE-22)

2026-06-25 GitHub_M

GHSA-v23m-ccfg-pq9h

Path Traversal Pnpm Red Hat

7.1

CVSS 3.1 · Vendor: GitHub_M

Severity by source

Vendor (GitHub_M) PRIMARY

7.1 HIGH

AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L

vuln.today AI

7.1 HIGH

Registry-controlled input over the network (AV:N, PR:N) but the victim must run stage download (UI:R); arbitrary file overwrite gives I:H with A:L and no confidentiality impact (C:N).

3.1 AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L

4.0 AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N

Red Hat

7.1 HIGH

qualitative

Primary rating from Vendor (GitHub_M).

CVSS VectorVendor: GitHub_M

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

Low

Lifecycle Timeline

Patch available

Jun 25, 2026 - 19:17 EUVD

Source Code Evidence Fetched

Jun 25, 2026 - 18:17 vuln.today

Analysis Generated

Jun 25, 2026 - 18:17 vuln.today

DescriptionCVE.org

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.

AnalysisAI

Path traversal in pnpm's pnpm stage download command (versions 11.3.0 through 11.5.2) lets a malicious or compromised registry overwrite arbitrary files reachable by the user running the command. The tool built a local tarball filename directly from registry-controlled package name and version fields, so a crafted manifest (e.g. a version like 1.0.0/../../evil) escaped the intended download directory. This is fixed in 11.5.3; no public exploit identified at time of analysis, though the fixing PR (#12303) includes proof-of-traversal test cases.

Technical ContextAI

pnpm is a widely-used Node.js package manager; the affected code lives in its release/staging tooling (@pnpm/releasing.commands). The vulnerable function derived an output filename via a naive normalizePackageName(name) (only stripping @ and /) concatenated with the raw version field and a stage ID, then passed it to path.resolve() and fs.writeFile(). Because neither field was validated, embedded path separators and ../ sequences in the manifest's name or version survived into the resolved path, producing a classic CWE-22 (Improper Limitation of a Pathname to a Restricted Directory / path traversal). The merged fix introduces createTarballFilename(), which validates the package name with validate-npm-package-name, validates the version with semver valid(), rejects any filename whose path.basename (POSIX and win32) differs from itself, and additionally verifies that the final resolved destination's directory equals the intended download directory before writing.

RemediationAI

Vendor-released patch: upgrade to pnpm 11.5.3 or later, which validates package name and version fields and verifies the write destination stays within the download directory. As a compensating control until upgrade, avoid running pnpm stage download against untrusted or third-party registries, and pin staging operations to a known-good internal registry you control; running the command from an isolated/ephemeral working directory with no sensitive sibling files limits the blast radius of any overwrite, at the cost of extra workflow steps. Review advisory GHSA-v23m-ccfg-pq9h (https://github.com/pnpm/pnpm/security/advisories/GHSA-v23m-ccfg-pq9h) and the fix in https://github.com/pnpm/pnpm/pull/12303 for details.