CVE-2026-47135: vm2: Sandbox escape via unblocked cross-realm Symbol.for keys + missing bridge write-trap symbol checks

Description

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.

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

Attack vector

Network

Complexity

High

Privileges

None

User interaction

None

Confidentiality

High

Integrity

High

Availability

None

Scope

Changed

Exploitation

Is it being used?

Exploit prediction (EPSS)0.3% · higher than 19% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

VM

vm2 · patriksimek

< 3.11.4 · source: vendor