CVE-2026-92951: vm2 (npm)

Should you act?

Critical, preconditions apply

Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
EPSS 0.5%, percentile 45: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 45% 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.
Only applies if your dependency tree includes vm2 (npm) <= 3.11.6, fixed in 3.11.7. Check your lockfile, including transitive dependencies.
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 before 3.11.7 contains an incorrect authorization vulnerability in the external package allowlist check that uses non-exact substring matching instead of full package-name boundary validation. Attackers can bypass the allowlist by requiring a colliding package name that contains an allowlisted package substring, causing vm2 to load and execute unauthorized host packages in the host context.

From the GitHub advisory

Summary

vm2 is a sandbox library for isolating and executing untrusted JavaScript code inside a Node.js process. It can restrict access to built-in modules and external packages.

When NodeVM enables an external allowlist together with a custom resolve callback, vm2 checks the requested package name with a non-exact match. For example, if the allowlist only permits left-pad, an attacker can still bypass the check with a colliding package name such as evil-left-pad, because it contains the allowlisted name.

If the colliding package already exists in a host path resolvable by the custom resolver, or if the target application's custom resolver / dependency-management workflow downloads the package and places it in a resolvable path, vm2 loads and executes that package in the host context. This lets sandboxed code bypass the module allowlist and may further lead to host code execution.

Details

Weakness type: CWE-706, CWE-829, CWE-863.

Product: vm2 (npm) · Assigned by: VulnCheck · Published: 2026-09-17

Affected and fixed versions

Ecosystem	Package	Vulnerable	First fixed
npm	`vm2`	<= 3.11.6	3.11.7

Vendor	Product	Affected versions (per CVE record)
patriksimek	vm2	< 3.11.7

Severity scores

Scored by	CVSS	Score	Vector
VulnCheck	4.0	9.4 Critical	`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`
VulnCheck	3.1	9.9 Critical	`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`
GitHub	3.1	9.9	`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`

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 none, automatable no, technical impact total.
FIRST EPSS (model of 2026-10-21): 0.54% probability of exploitation activity in the next 30 days; percentile 45.

Timeline

2026-08-17 — erroneo.us brief: vm2: 22 Critical Sandbox Escapes, Fixed in 3.12.2
2026-09-17 — CVE record last updated
2026-09-17 — CVE record published by VulnCheck
2026-10-01 — GitHub-reviewed advisory GHSA-c48m-32m9-vx93 published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.