Summary
vm2: External module allowlist uses a raw prefix test, so a prefix-sharing sibling package is treated as allowlisted
isPathAllowedForModule decides whether a resolved path belongs to an allowlisted external module using a raw string prefix test. node_modules/foo2 starts with node_modules/foo, so a package whose name merely shares a prefix with an allowlisted one is treated as being inside it, and a relative require from the allowlisted package reaches it even with transitive loading disabled.
Where it is
lib/resolver-compat.js, lines 122 to 132, quoted from HEAD 7a1f5100b96f48d34e0fe104ab37c0acc5944f92:
isPathAllowedForModule(path, mod) {
if (!super.isPathAllowed(path)) return false;
if (mod) {
if (mod.allowTransitive) return true;
if (path.startsWith(mod.path)) {
const rem = path.slice(mod.path.length);
if (!/(?:^|[\\/])node_modules(?:$|[\\/])/.test(rem)) return true;
}
}
return this.externals.some(regex => regex.test(path));
}
With mod.path of .../node_modules/foo and a resolved path of .../node_modules/foo2/index.js, startsWith is true and rem is 2/index.js, which contains no node_modules segment, so the function returns true.
The node_modules test in rem is what stops a genuine transitive dependency from slipping through. It does not stop a sibling, because a sibling's remainder never contains that segment.
Reachability
NodeVM.run at lib/nodevm.js:506 executes the script. require comes from createRequireForModule at lib/setup-node-sandbox.js:168-172 and reaches the resolver callback at lib/nodevm.js:380-384. LegacyResolver.resolveFull at lib/resolver-compat.js:145-160 sets currMod for direct requires, the relative specifier resolves through DefaultResolver.resolveFull and tryFile at lib/resolver.js:327-330, and the authorization decision lands on the function above.
Impact
Code running in NodeVM under an external module allowlist with transitive: false can reach a package that was not allowlisted, provided an allowlisted package performs a relative require to a prefix-sharing sibling.
Two preconditions are worth stating plainly rather than leaving implicit. The deployment must already have such a package layout, and an allowlisted package must have a reachable code path that does the relative require. This is not something the attacker creates; it is something they find. That narrows it considerably, and it is why I have not scored it higher.
Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.
CVE-2026-92945 has a CVSS score of 4.2 (Medium). The vector is network-reachable, low 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 (3.11.7); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Require a separator after the prefix, so a sibling cannot match:
if (path === mod.path || path.startsWith(mod.path + path.sep)) {
That is the same anchoring the rem regex already applies to node_modules, applied one level earlier.
Frequently Asked Questions
- What is CVE-2026-92945? CVE-2026-92945 is a medium-severity path traversal vulnerability in vm2 (npm), affecting versions <= 3.11.6. It is fixed in 3.11.7. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
- How severe is CVE-2026-92945? CVE-2026-92945 has a CVSS score of 4.2 (Medium). 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.
- Which versions of vm2 are affected by CVE-2026-92945? vm2 (npm) versions <= 3.11.6 is affected.
- Is there a fix for CVE-2026-92945? Yes. CVE-2026-92945 is fixed in 3.11.7. Upgrade to this version or later.
- Is CVE-2026-92945 exploitable, and should I be worried? Whether CVE-2026-92945 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
- What actually determines whether CVE-2026-92945 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.
- How do I fix CVE-2026-92945? Upgrade
vm2to 3.11.7 or later.