vm2: Sandbox escape via unblocked cross-realm Symbol.for keys + missing bridge write-trap symbol checks
CVE-2026-47135
8.7HIGH
What is CVE-2026-47135?
vm2 is an open source vm/sandbox for Node.js. Prior to version 3.11.4, 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. This issue has been patched in version 3.11.4.
Affected Version(s)
vm2 < 3.11.4