Privilege escalation in Patriksimek Vm2
CVE-2026-92957
vm2 through 3.11.6 does not normalize `node:`-prefixed builtin specifiers when evaluating user-supplied negative (deny) entries in a NodeVM wildcard require policy. Although NodeVM strips the `node:` prefix during require() resolution, negative wildcard entries are matched by exact string comparison against the canonical builtin names, so a policy such as `new NodeVM({ require: { builtin: ['*', '-node:child_process'] } })` fails to deny the canonical `child_process` module. Sandboxed code can therefore obtain the host `child_process` builtin via `require('child_process')` or `require('node:child_process')`, gaining references to process-spawning APIs such as execSync and spawn, which is equivalent to host command-execution capability for untrusted sandbox code. Fixed in vm2 3.11.7. (Suggested title: "vm2 before 3.11.7: NodeVM builtin deny-list bypass via node:-prefixed specifiers exposes child_process")
Vulnerability class: Privilege Escalation
CVSS v3 metric
CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.
Affected products
Weakness classification (CWE)
References
- disclosure@vulncheck.com (vendor-advisory)
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2026-92957?
- CVE-2026-92957 is a critical-severity vulnerability in Patriksimek Vm2, classified under Improper Privilege Management. CVSS score: 9.9/10. Published 2026-09-17.
- How severe is CVE-2026-92957?
- Critical severity. CVSS v3 base score is 9.9 out of 10.