isolated-vm sandbox escape turns one reference into host RCE
Endor Labs found a type confusion in isolated-vm's ExternalCopy that lets sandboxed JavaScript corrupt host memory, escalating from a single ivm.Reference to full guest-to-host control-flow hijack. Tracked as GHSA-864f-rcv7-6rh4 (CVE pending), it hits all versions through 7.0.0 and is patched in 6.2.0/7.0.1. The V8 Isolate boundary held — the marshal layer didn't. For a sandbox with ~1M weekly npm downloads behind AI-agent tooling, that's a serious trust breach.