Security Digest · Vulnerability record
CVE-2026-92958: vm2 before 3.11.7 Denylist Bypass via fs/promises
vm2 through 3.11.6 contains a builtin-module denylist bypass in NodeVM.
CVSS 8.4 High EPSS 0.4% · p31 Check exposure
Should you act?
Normal patch cycle
No exploitation signal; fix it in your next routine update if you are affected. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.4%, percentile 31: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 31% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Editorial verdict: Check exposure. vm2: 22 Critical Sandbox Escapes, Fixed in 3.12.2 — If anything outside your trust boundary can get code into vm2, upgrade to 3.12.2 today and plan to move that code out of process; if vm2 only runs your own code, upgrade on a normal cycle.
What it is
vm2 through 3.11.6 contains a builtin-module denylist bypass in NodeVM. When the embedder uses the builtin wildcard together with negative entries (e.g. require: { builtin: ['', '-fs', '-childprocess'] }), negative entries are matched by exact module name in lib/builtin.js, so -fs removes only the builtin named fs and does not remove builtin subpaths such as fs/promises. Sandboxed code can therefore call require('fs/promises') or require('node:fs/promises') and reach the promise-based filesystem API despite fs being denied; node: prefix handling is likewise inconsistent (a -node:fs/promises entry does not block require('fs/promises')). Host file creation and writing were confirmed via fsp.writeFile(), and other fs/promises operations (cp, mkdir, rename, rm, rmdir, truncate, read operations, etc.) are also reachable. This issue is fixed in vm2 3.11.7.
Weakness type: CWE-269.
Product: patriksimek vm2 · Assigned by: VulnCheck · Published: 2026-09-17
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| patriksimek | vm2 | < 3.11.7 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| VulnCheck | 4.0 | 8.4 High | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:H/SA:L |
| VulnCheck | 3.1 | 8.5 High | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Attack requirements: none
- Privileges required: low (any account)
- User interaction: none
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc, automatable no, technical impact partial.
- FIRST EPSS (model of 2026-10-21): 0.38% probability of exploitation activity in the next 30 days; percentile 31.
Timeline
- — erroneo.us brief: vm2: 22 Critical Sandbox Escapes, Fixed in 3.12.2
- — CVE record published by VulnCheck
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
Vulnerability records
- CVE.org record CVE-2026-92958 cve.org
- NVD entry CVE-2026-92958 nvd.nist.gov