CVE-2026-92949: vm2: vm.freeze()/vm.readonly() bypass via accessor descriptor

Untrusted JavaScript running inside new VM().run() / new NodeVM().run() can bypass vm.freeze() / vm.readonly() and mutate a host object the embedder explicitly marked read-only - the documented contract is “prevent sandboxed scripts from adding, changing, or deleting properties”. If the frozen host object has an accessor (get/set) own-property, the sandbox can read the host setter back out via Object.getOwnPropertyDescriptor() and call it directly; the call lands in BaseHandler.apply which unwraps the readonly proxy to the raw host object and runs the host setter against it. No non-default VM/NodeVM options are required; the only precondition is that the embedder froze an object whose shape includes an accessor property. A second route to the same sink exists via __lookupSetter__.