CVE-2026-82393 is a high-severity (CVSS 7.5) Path Traversal vulnerability in pnpm. A fix is available for pnpm — see the affected versions and patch details below.
pnpm: A tarball dependency's manifest `name` escapes node_modules → arbitrary file write/overwrite on install
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-82393.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-82393 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 390,807 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
pnpmnpmDescription
Summary
When resolving a package, pnpm uses the resolved manifest name as a raw path segment for the isolated-linker import target. A tarball dependency whose package.json name is a scoped path traversal (@x/../../…/<abs path>) is therefore extracted outside node_modules, to an attacker-chosen absolute path, and can overwrite existing files there. Attacker controls the destination, filenames, and contents → arbitrary file write → code execution (e.g. ~/.zshrc, .git/hooks/pre-commit, another package's code). Occurs during pnpm install even with --ignore-scripts (no lifecycle scripts run), defeating that safety.
Same class as the just-patched GHSA-hwx4 (transitive-dependency alias traversal) and GHSA-v23m (stage download manifest name/version traversal), in a sink their fixes did not cover: the isolated-linker import target keyed by the resolved name.
Root cause
- The isolated-linker import target is built with a raw
path.join(modules, <resolved name>)ininstalling/deps-resolver/src/resolvePeers.ts:706,installing/deps-resolver/src/index.ts:614, anddeps/graph-builder/src/lockfileToDepGraph.ts:233— without thesafeJoinModulesDirguard used on the symlink/hoisted/bin paths (installing/deps-restorer/src/lockfileToHoistedDepGraph.ts:222). The store location isnode_modules/.pnpm/<id>/node_modules/<name>, so a traversal<name>escapes. - The only resolve-time name gate (
resolving/npm-resolver/src/pickPackage.ts:753) rejects only unscoped names containing/, so a scoped@x/../..passes.
Steps to reproduce
Self-contained PoC (real [email protected]; loopback tarball server; escape target is a throwaway temp dir):
npm i [email protected]
# host a tarball whose package.json name = "@x/"+"../".repeat(25)+"<abs>/OUTSIDE"; victim depends on the http URL
pnpm install --ignore-scripts
Confirmed output (repro/poc.mjs, exit 0):
escape dir is outside the project : true
new file implanted outside node_modules : true
pre-existing file OVERWRITTEN : true
*** CONFIRMED: a tarball dependency wrote & overwrote files OUTSIDE the project during `pnpm install --ignore-scripts` ***
Remediation
Route the isolated-linker import-target joins (resolvePeers.ts:706, deps-resolver/index.ts:614, lockfileToDepGraph.ts:233) through safeJoinModulesDir (as the hoisted linker already does), and/or enforce validate-npm-package-name on the resolved manifest name (close the scoped-name gap at pickPackage.ts:753) so the import target rejects a traversal name and re-asserts containment before any write.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | pnpm | all versions | 10.34.5npm install pnpm@10.34.5 |
| 📦npm | pnpm | ≥ 11.0.0&&< 11.11.0 | 11.11.0npm install pnpm@11.11.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pnpm, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update pnpm to 10.34.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-82393 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This Important vulnerability in pnpm allows arbitrary file write and code execution through a path traversal flaw during tarball dependency installation. An attacker can craft a malicious package.json manifest with a scoped path traversal to overwrite arbitrary files outside the `node_modules` directory, even when…
To mitigate this issue, Red Hat recommends avoiding the installation of untrusted or unverified pnpm packages. When installing pnpm dependencies, ensure that the source is trusted and that the integrity of the packages is verified. If possible, execute pnpm install operations within isolated and minimally privileged environments, such as containers with restricted filesystem access, to limit the potential blast radius of any exploitation.Source: Red Hat security advisory for CVE-2026-82393 (CC BY 4.0)
Frequently Asked Questions
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