CVE-2026-44007: vm2 NodeVM `nesting: true` bypasses `require: false` allowing sandbox escape and arbitrary OS command execution

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.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 0.6%, percentile 49: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 49% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Needs an account (high (admin)). Exposure depends on who can log in.
• Only applies if your dependency tree includes vm2 (npm) <= 3.11.0, fixed in 3.11.1. Check your lockfile, including transitive dependencies.

What it is

vm2 is an open source vm/sandbox for Node.js. Prior to 3.11.1, when a NodeVM is created with nesting: true, sandbox code can unconditionally require('vm2') regardless of the outer VM's require configuration — including require: false. With access to vm2, the sandbox constructs a new inner NodeVM with its own unrestricted require settings and executes arbitrary OS commands on the host. Any application that runs untrusted code inside a NodeVM with nesting: true is fully compromised. This vulnerability is fixed in 3.11.1.

From the GitHub advisory

Summary

When a NodeVM is created with nesting: true, sandbox code can unconditionally require('vm2') regardless of the outer VM's require configuration — including require: false. With access to vm2, the sandbox constructs a new inner NodeVM with its own unrestricted require settings and executes arbitrary OS commands on the host. Any application that runs untrusted code inside a NodeVM with nesting: true is fully compromised.

Details

The vulnerability is in how the nesting: true option interacts with the legacy module resolver.

lib/nodevm.js:96-99 — NESTINGOVERRIDE is a special builtin map that injects the vm2 package into the sandbox:

Weakness type: CWE-284, CWE-1100, CWE-693.

Product: vm2 (npm) · Assigned by: GitHub_M · Published: 2026-05-13

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: high (admin)
• User interaction: none
• Scope: changed (can affect other components)

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 total.
• FIRST EPSS (model of 2026-10-21): 0.61% probability of exploitation activity in the next 30 days; percentile 49.

Timeline

• 2026-05-07 — GitHub-reviewed advisory GHSA-8hg8-63c5-gwmx published (critical)
• 2026-05-13 — CVE record published by GitHub_M
• 2026-09-07 — 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

1. access.redhat.com access.redhat.com

Vulnerability records

1. GitHub Advisory GHSA-8hg8-63c5-gwmx github.com
2. CVE.org record CVE-2026-44007 cve.org
3. NVD entry CVE-2026-44007 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. openwall.com openwall.com
3. access.redhat.com access.redhat.com
4. RHBZ#2477198 bugzilla.redhat.com
5. security.access.redhat.com security.access.redhat.com
6. github.com github.com

Critical npm advisories · Today’s Security Digest