vm2: NodeVM builtin denylist bypass via fs/promises despite -fs, allowing host filesystem writes
## Summary NodeVM's builtin wildcard policy can allow sandboxed code to access `fs/promises` even when the embedder denies `fs`. With the following configuration: ```js require: { builtin: ['*', '-fs', '-child_process'] } ``` `require('fs')` and `require('child_process')` are blocked, but `require('fs/promises')` and `require('node:fs/promises')` are still available. This allows sandboxed code to create and write files on the host filesystem through the promise-based filesystem API. ## Affected Mode NodeVM. ## Affected Configuration ```js new NodeVM({ require: { builtin: ['*', '-fs', '-child_process'] } }); ``` This affects configurations where users rely on negative builtin entries such as `-fs` to deny filesystem access while using the `'*'` builtin wildcard. ## Affected Files / Functions - `lib/builtin.js` - `DANGEROUS_BUILTINS` - `BUILTIN_MODULES` - `makeBuiltinsFromLegacyOptions` - `addDefaultBuiltin` - `lib/resolver.js` - `Resolver.resolve` - `Resolver.loadBuiltinModule` - `lib/setup-node-sandbox.js` - `requireImpl` ## Root Cause `lib/builtin.js` builds `BUILTIN_MODULES` from Node's builtin module list and filters dangerous/default-denied modules. In wildcard mode, negative entries are checked by exact name: ```js if (builtins.indexOf(`-${name}`) === -1) { addDefaultBuiltin(res, name, hostRequire); } ``` This means `-fs` removes only the exact builtin named `fs`. It does not remove builtin subpaths such as `fs/promises`. There is also inconsistent `node:` prefix handlin
GHSA-6rh5-qq4q-97xh
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:GHSA-6rh5-qq4q-97xh
vm2
Source reference: /affected/0/package/name
- Affected versions
- Not stated in this record
- Fixed versions
- 3.11.7
Source reference:
/affected/0/ranges - Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"type": "SEMVER",
"events": [
{
"introduced": "0"
},
{
"fixed": "3.11.7"
}
]
}
],
"package": {
"name": "vm2",
"purl": "pkg:npm/vm2",
"ecosystem": "npm"
},
"database_specific": {
"source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-6rh5-qq4q-97xh/GHSA-6rh5-qq4q-97xh.json",
"last_known_affected_version_range": "<= 3.11.6"
}
}
]- Related CVEs
- CVE-2026-92958
Source reference:
/aliases
Publisher severity
high
Source reference: /database_specific/severity
- Event
- #61270 · Revision 1
- Added to Heist Feed
- Publisher date