CVE-2026-23888
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
pnpmReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
pnpm is a package manager. Prior to version 10.28.1, 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. The issue impacts all pnpm users who install packages with binary assets, users who configure custom Node.js binary locations and CI/CD pipelines that auto-install binary dependencies. It can lead to overwriting config files, scripts, or other sensitive files leading to RCE. Version 10.28.1 contains a patch.
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 CVE-2026-23888 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 CVE-2026-23888 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 CVE-2026-23888. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-23888 in your dependencies?
O3 detects CVE-2026-23888 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.