Vulnerability in Patriksimek Vm2
CVE-2026-92956
vm2 versions 3.10.1 through 3.11.6 contain a sandbox escape reachable from a default `new VM()` sandbox when running on Node.js 26. WebAssembly.compileStreaming and WebAssembly.instantiateStreaming can produce a raw host-realm Promise that rejects with a host-realm error object; by controlling Symbol.species via Promise.prototype.finally, sandbox code receives that raw host error, walks from the host error constructor to the host Function constructor, and recovers the real host `process` object, gaining host Node.js capabilities (e.g. access to host modules such as fs) in the context of the process running the sandbox. No NodeVM, require permission, host object injection, or otherwise unsafe configuration is required. This is a bypass of the fix for GHSA-6j2x-vhqr-qr7q, which removed the JSPI entry points WebAssembly.promising and WebAssembly.Suspending. The issue is fixed in 3.11.7.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.005 (43.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 43.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.005 · change: -0.001
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/patriksimek/vm2/security/advisories/GHSA-wjwh-qqvp-g4p4 (vendor-advisory)
- www.vulncheck.com/advisories/vm2-3.10.1-through-3.11.6-sandbox-escape-via-webas… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-92956?
- CVE-2026-92956 is a critical-severity vulnerability in Patriksimek Vm2, classified under Protection Mechanism Failure. CVSS score: 10.0/10. Published 2026-09-17.
- How severe is CVE-2026-92956?
- Critical severity. CVSS v3 base score is 10.0 out of 10.
- Is CVE-2026-92956 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.