CVE-2026-47135: vm2 has a sandbox escape via unblocked cross-realm Symbol.for keys + missing bridge write…

Summary vm2 3.11.2 Symbol.for override in setup-sandbox.js only intercepts 2 of 9 dangerous Node.js cross-realm symbols. Combined with the bridge's set/defineProperty/deleteProperty traps having no isDangerousCrossRealm…

8.7CVSS Score

HIGHSeverity

NOCISA KEV

VulnerabilityImpact Type

📋 Vulnerability Details

CVE ID	CVE-2026-47135
Vendor	npm
Affected Product	vm2
Vulnerability Type	Vulnerability
CVSS Score	8.7 (HIGH)
Actively Exploited	❌ No known exploitation
Patch Status	See Vendor Advisory →
Reported By	CYBERDUDEBIVASH SENTINEL APEX Intelligence (via github_advisories)

🔬 Technical Analysis

Summary vm2 3.11.2 `Symbol.for` override in `setup-sandbox.js` only intercepts 2 of 9 dangerous Node.js cross-realm symbols. Combined with the bridge's `set`/`defineProperty`/`deleteProperty` traps having no `isDangerousCrossRealmSymbol` key check, sandbox code can obtain real cross-realm symbols, write them to host objects, and control host-side behavior — verified with a full `util.promisify` hijack chain.

Root Cause 1. Incomplete `Symbol.for` override (`setup-sandbox.js:132-142`): ```js`

Symbol.for = function (key) { const keyStr = '' + key; if (keyStr === 'nodejs.util.inspect.custom') return blockedSymbolCustomInspect; if (keyStr === 'nodejs.rejection') return blockedSymbolRejection; return originalSymbolFor(keyStr); // everything else passes through }; ` Only inspect.c

📚 Advisory References

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