Executive brief
vm2 is a popular Node.js sandbox library used to safely execute untrusted code. A prototype pollution vulnerability allows attackers to break out of the sandbox and execute arbitrary code on the host system. This can lead to complete system compromise when vm2 is used to run untrusted scripts.
Technical details
The vulnerability is a prototype pollution attack in vm2 before version 3.9.4 that exploits the JavaScript prototype chain to escape the sandbox. The attack manipulates object prototypes to modify behavior of sandboxed code execution, allowing an attacker to override security controls and execute arbitrary code on the host machine. No authentication or special user interaction is required—malicious code executed within the vm2 sandbox can trigger the escape. The vulnerability was patched in version 3.9.4; users must upgrade immediately to remediate the risk.
Affected products
- vm2 vm2 before 3.9.4
Timeline
- 2021-09-07: disclosed
- 2021-10-18: advisory
- 2021-10-19: patched