CVE-2026-47137: vm2 has a CVE-2023-37903 patch bypass: nesting:true without explicit require still allows full RCE

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. 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 0.7%, percentile 53: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 53% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes vm2 (npm) <= 3.11.3, fixed in 3.11.4. Check your lockfile, including transitive dependencies.

What it is

vm2 is an open source vm/sandbox for Node.js. Prior to version 3.11.4, the fix for GHSA-8hg8-63c5-gwmx (CVE-2023-37903) introduced a check in nodevm.js line 263 that blocks the combination nesting: true + require: false. However, the check uses strict equality (options.require === false), which is trivially bypassed by omitting the require option entirely. When require is not specified, options.require is undefined, not false. The strict equality check fails, so the security guard is skipped. Immediately after (line 280), the destructuring default require: requireOpts = false assigns requireOpts = false, producing the exact configuration the patch was designed to prevent. This issue has been patched in version 3.11.4.

From the GitHub advisory

Summary

The fix for GHSA-8hg8-63c5-gwmx (CVE-2023-37903) introduced a check in nodevm.js line 263 that blocks the combination nesting: true + require: false. However, the check uses strict equality (options.require === false), which is trivially bypassed by omitting the require option entirely.

When require is not specified, options.require is undefined, not false. The strict equality check fails, so the security guard is skipped. Immediately after (line 280), the destructuring default require: requireOpts = false assigns requireOpts = false, producing the exact configuration the patch was designed to prevent.

Root Cause

Impact

Weakness type: CWE-913.

Product: vm2 (npm) · Assigned by: GitHub_M · Published: 2026-06-12

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• 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 yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.70% probability of exploitation activity in the next 30 days; percentile 53.

Timeline

• 2026-05-29 — GitHub-reviewed advisory GHSA-m4wx-m65x-ghrr published (critical)
• 2026-06-12 — CVE record published by GitHub_M
• 2026-06-13 — CVE record last updated

Sources and references

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

Vulnerability records

1. GitHub Advisory GHSA-m4wx-m65x-ghrr github.com
2. CVE.org record CVE-2026-47137 cve.org
3. NVD entry CVE-2026-47137 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com
4. github.com github.com
5. github.com github.com

Critical npm advisories · Today’s Security Digest