CVE-2026-47209
Published: 12 June 2026
Summary
CVE-2026-47209 is a high-severity Protection Mechanism Failure (CWE-693) vulnerability. Its CVSS base score is 8.6 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Escape to Host (T1611); ranked at the 20.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-36440
Vulnerability details
vm2 is an open source vm/sandbox for Node.js. Prior to version 3.11.4, the BaseHandler.set trap in bridge.js (line 1231) ignores the receiver parameter and unconditionally writes to the host target object. Per the Proxy set trap specification, when receiver !==…
more
proxy (e.g., when a child object inherits from the proxy via Object.create), the property assignment should create an own property on the receiver, not on the proxy target. The current implementation always calls otherReflectSet(object, key, value) against the host target, causing all inherited property writes to leak through to the host object. This bug provides an alternative attack vector for writing dangerous cross-realm Symbol keys (e.g., nodejs.util.promisify.custom) to host objects, bypassing any future per-trap isDangerousCrossRealmSymbol guard on the direct set path. This issue has been patched in version 3.11.4.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Sandbox escape via proxy set trap allowing cross-realm writes to host objects directly enables T1611 Escape to Host.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Implements a reliable, tamperproof protection mechanism whose completeness can be assured.
Procedures for training on protection mechanisms reduce the chance of protection mechanism failures being present or exploitable.
Documented procedures to implement assessment, authorization, and monitoring controls prevent these protection mechanisms from failing due to undefined processes.
Direct evaluation of whether controls produce desired security outcomes detects protection mechanism failures and enables remediation.
Requires assessment that protection mechanisms are correctly implemented and producing intended security outcomes.
The POA&M process ensures identified weaknesses in protection mechanisms are documented and scheduled for remediation, reducing the duration they remain exploitable.
Ongoing control assessments and analysis of monitoring data enable timely detection and response when protection mechanisms fail.
Impact analysis identifies changes that could weaken or disable existing protection mechanisms.