vm2 before 3.12.2 Authorization Bypass via Custom Resolver
Summary
| CVE | CVE-2026-100721 |
|---|---|
| State | PUBLISHED |
| Assigner | VulnCheck |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-27 02:17:17 UTC |
| Updated | 2026-09-28 17:17:46 UTC |
| Description | vm2 before 3.12.2 contains an authorization bypass in the NodeVM external-module resolver. When an embedder configures `require.external` with a custom resolver (and `context: 'host'`), `LegacyResolver.customResolve` in lib/resolver-compat.js records the resolved module directory in `this.externals` as `new RegExp('^' + escapeRegExp(resolvedPath))`, without requiring a path separator or end-of-string boundary. Untrusted guest code can therefore require the allowlisted module (e.g. `foo`) and then require the absolute path of a non-allowlisted sibling whose path merely shares the resolved prefix (e.g. `.../node_modules/foo2/index.js`); the sibling passes `isPathAllowedForModule` and is loaded through `hostRequire`, so its top-level code runs in the host process before the exports are wrapped with `vm.readonly`, resulting in a sandbox escape and arbitrary code execution in the host context. |
Risk And Classification
Primary CVSS: v4.0 9.5 CRITICAL from [email protected]
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS: 0.004000000 probability, percentile 0.316170000 (date 2026-09-27)
Problem Types: CWE-863 | CWE-863 Incorrect Authorization
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 9.5 | CRITICAL | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/C... |
| 4.0 | CNA | CVSS | 9.5 | CRITICAL | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H |
| 3.1 | [email protected] | Secondary | 9 | CRITICAL | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H |
| 3.1 | CNA | CVSS | 9 | CRITICAL | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
PresentPrivileges Required
NoneUser Interaction
NoneConfidentiality
HighIntegrity
HighAvailability
HighSub Conf.
HighSub Integrity
HighSub Availability
HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
NoneUser Interaction
NoneScope
ChangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Patriksimek | Vm2 | affected 3.12.2 semver | Not specified |
| CNA | Patriksimek | Vm2 | unaffected 3.12.2 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| www.vulncheck.com/advisories/vm2-before-3.12.2-authorization-bypass-via-custom-... | [email protected] | www.vulncheck.com | |
| github.com/patriksimek/vm2/security/advisories/GHSA-5h3f-q97h-ccvc | [email protected] | github.com | |
| github.com/patriksimek/vm2/commit/ab4ee7d803e8c80155e9eb3672226bddbca4aa9c | [email protected] | github.com | |
| github.com/patriksimek/vm2/commit/6ac3916da84e060c403e407b6b6318fcc66b0e72 | [email protected] | github.com | |
| github.com/patriksimek/vm2/commit/91034466bfb7f56b95fd48083ec6ca36d058f164 | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: rexpository (en)
There are currently no legacy QID mappings associated with this CVE.