Vulnerability · Published Jun 12, 2026 · Assigned by GitHub_M

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

High 8.7

In plain English

A high-severity security flaw in vm2 from patriksimek. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 19% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.7High

Exploit odds (30 days)0.3%top 81.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	vm2	3.11.4	GHSA-m5q2-4fm3-vfqp

Affected products (as reported)

Vendor	Product	Versions
patriksimek	vm2	< 3.11.4

Weakness: CWE-693 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

References

https://github.com/patriksimek/vm2/security/advisories/GHSA-m5q2-4fm3-vfqp x_refsource_CONFIRM
https://github.com/patriksimek/vm2/commit/928aef51898b5c52a05f05a40c4cfeb52e172878 x_refsource_MISC
https://github.com/patriksimek/vm2/releases/tag/v3.11.4 x_refsource_MISC