{"id":"CVE-2026-82393","aliases":["GHSA-vq4v-j7r6-jq4m"],"url":"https://o3.security/vulnerability/CVE-2026-82393","summary":"pnpm: A tarball dependency's manifest `name` escapes node_modules → arbitrary file write/overwrite on install","details":"## Summary\nWhen 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.\n\nSame 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**.\n\n## Root cause\n- The isolated-linker import target is built with a raw `path.join(modules, <resolved name>)` in `installing/deps-resolver/src/resolvePeers.ts:706`, `installing/deps-resolver/src/index.ts:614`, and `deps/graph-builder/src/lockfileToDepGraph.ts:233` — **without** the `safeJoinModulesDir` guard used on the symlink/hoisted/bin paths (`installing/deps-restorer/src/lockfileToHoistedDepGraph.ts:222`). The store location is `node_modules/.pnpm/<id>/node_modules/<name>`, so a traversal `<name>` escapes.\n- The only resolve-time name gate (`resolving/npm-resolver/src/pickPackage.ts:753`) rejects only *unscoped* names containing `/`, so a **scoped** `@x/../..` passes.\n\n## Steps to reproduce\nSelf-contained PoC (real `pnpm@11.9.0`; loopback tarball server; escape target is a throwaway temp dir):\n```\nnpm i pnpm@11.9.0\n# host a tarball whose package.json name = \"@x/\"+\"../\".repeat(25)+\"<abs>/OUTSIDE\"; victim depends on the http URL\npnpm install --ignore-scripts\n```\nConfirmed output (`repro/poc.mjs`, exit 0):\n```\nescape dir is outside the project        : true\nnew file implanted outside node_modules  : true\npre-existing file OVERWRITTEN            : true\n*** CONFIRMED: a tarball dependency wrote & overwrote files OUTSIDE the project during `pnpm install --ignore-scripts` ***\n```\n\n## Remediation\nRoute 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.","published":"2026-08-31T21:12:09.196Z","modified":"2026-09-11T03:30:49.757241945Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"npm","name":"pnpm","fixedVersion":"10.34.5"},{"ecosystem":"npm","name":"pnpm","fixedVersion":"11.11.0"}],"fix":{"url":"https://github.com/pnpm/pnpm/commit/51300fd41c5e4c8f47635108e373cc3d1f324fa7","label":"pnpm/pnpm@51300fd"},"references":[{"type":"WEB","url":"https://github.com/pnpm/pnpm/releases/tag/v10.34.5"},{"type":"WEB","url":"https://github.com/pnpm/pnpm/releases/tag/v11.11.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/82xxx/CVE-2026-82393.json"},{"type":"ADVISORY","url":"https://github.com/pnpm/pnpm/security/advisories/GHSA-vq4v-j7r6-jq4m"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-82393"},{"type":"FIX","url":"https://github.com/pnpm/pnpm/commit/51300fd41c5e4c8f47635108e373cc3d1f324fa7"},{"type":"FIX","url":"https://github.com/pnpm/pnpm/commit/78e29fe5583a1e5d69ea05e414eff310f78d5ed9"},{"type":"FIX","url":"https://github.com/pnpm/pnpm/pull/12872"},{"type":"FIX","url":"https://github.com/pnpm/pnpm/pull/12890"},{"type":"PACKAGE","url":"https://github.com/pnpm/pnpm"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-11T03:30:49.757241945Z"}}