CVE-2026-59871: node-tar Process Crash Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-w8wr-v893-vjvp",
  "modified" : "2026-07-20T21:53:14Z",
  "published" : "2026-07-20T21:53:14Z",
  "aliases" : [ "CVE-2026-59871" ],
  "summary" : "node-tar: Process crash via PAX numeric path type confusion",
  "details" : "### Summary\n\nA crafted 2.5KB tar archive crashes any Node.js process that extracts it. The PAX header parser coerces all-digit path values to JavaScript numbers, which causes an uncaught TypeError when downstream code calls `.split('/')` on the numeric value. Error handlers and `strict: false` cannot intercept the crash.\n\n### Details\n\nIn `pax.ts` line 180, `parseKV` converts PAX values matching `/^[0-9]+$/` to numbers via `+v`. This applies to all fields including `path` and `linkpath`. When a PAX header sets `path` to an all-digit string like `\"12345\"`, the value becomes the number `12345`.\n\nThis number flows through Header -> ReadEntry -> Unpack.CHECKPATH, where `normalizeWindowsPath(entry.path).split('/')` throws a TypeError because numbers don't have `.split()`.\n\nThe throw is synchronous during event emission and bypasses all error handling:\n- `strict: false` does not help\n- `'error'` event handlers do not catch it\n- `'warn'` handlers do not catch it\n- The TypeError propagates through the event emitter stack as an uncaughtException\n\nDirectory, SymbolicLink, and Link type entries reach CHECKPATH and crash. File type entries crash earlier in Header constructor at `this.path.slice(-1)`, but that throw is caught and emitted as a warning only.\n\n### PoC\n\nCreate a tar archive with a PAX extended header containing an all-digit path:\n\n```\nPAX header body: \"18 path=12345\\n\"\nEntry type: Directory (type '5')\n```\n\nExtract it:\n```js\nconst tar = require('tar');\n\n// All of these crash with TypeError: t.split is not a function\ntar.extract({ file: 'malicious.tar', cwd: '/tmp/test' });\n\n// Error handlers don't help:\ntar.extract({ file: 'malicious.tar', cwd: '/tmp/test', strict: false })\n  .on('error', (err) => { /* never reached */ })\n  .on('warn', (code, msg) => { /* never reached */ });\n```\n\nThe archive is ~2.5KB. The crash is deterministic on every attempt.\n\n### Impact\n\nDenial of service. Any application or tool that extracts untrusted tar archives crashes from a single small file. This includes npm (which uses node-tar to extract packages), CI/CD pipelines, file upload processors, and backup tools. The crash cannot be caught by application-level error handling.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "tar"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "7.5.18"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 7.5.17"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/isaacs/node-tar/security/advisories/GHSA-w8wr-v893-vjvp"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-59871"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/isaacs/node-tar/commit/e02a4e9e013c4be95302e2eb2047a942b883c27b"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/isaacs/node-tar"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/isaacs/node-tar/releases/tag/v7.5.18"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-704" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-20T21:53:14Z",
    "nvd_published_at" : "2026-07-08T16:16:33Z"
  }
}