Summary
pnpm: A tarball dependency's manifest name escapes node_modules → arbitrary file write/overwrite on install
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` ***
Impact
Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.
CVE-2026-82393 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (10.34.5, 11.11.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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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.
Frequently Asked Questions
- What is CVE-2026-82393? CVE-2026-82393 is a high-severity path traversal vulnerability in pnpm (npm), affecting versions < 10.34.5. It is fixed in 10.34.5, 11.11.0. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
- How severe is CVE-2026-82393? CVE-2026-82393 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of pnpm are affected by CVE-2026-82393? pnpm (npm) versions < 10.34.5 is affected.
- Is there a fix for CVE-2026-82393? Yes. CVE-2026-82393 is fixed in 10.34.5, 11.11.0. Upgrade to this version or later.
- Is CVE-2026-82393 exploitable, and should I be worried? Whether CVE-2026-82393 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-82393 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-82393?
- Upgrade
pnpmto 10.34.5 or later - Upgrade
pnpmto 11.11.0 or later
- Upgrade