{"id":"CVE-2026-92959","title":"vm2 before 3.11.8 does not fully enforce the allowAsync: false option in VM and NodeVM","summary":"vm2 before 3.11.8 does not fully enforce the allowAsync: false option in VM and NodeVM. While localPromise.prototype.then is replaced with a handler that throws 'Async not available', the sandbox's Promise static methods (Promise.resolve…","severity":"high","cvss":7.1,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H","cwe":["CWE-693","CWE-358"],"vendor":"patriksimek","product":"vm2","affected":["vm2 < 3.11.8"],"published":"2026-09-17","updated":"2026-09-21","sourceUpdated":"2026-09-21T21:17:16.917","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-92959","references":[{"url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-f8gf-w286-fmq2","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/vm2-before-3.11.8-allowasync-bypass-via-promise-thenable","label":"disclosure@vulncheck.com"},{"url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-f8gf-w286-fmq2","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-92959.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-92959"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-92959"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-92959"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2536043"}],"tags":["nvd","cve.org","exploit-available","csaf","vex","red-hat"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-21T20:41:04.607286Z"},"epss":0.00256,"epssPercentile":0.17568,"ingestedAt":"2026-09-17T14:19:30.991Z","slug":"CVE-2026-92959","body":"## Overview\n\nvm2 before 3.11.8 does not fully enforce the allowAsync: false option in VM and NodeVM. While localPromise.prototype.then is replaced with a handler that throws 'Async not available', the sandbox's Promise static methods (Promise.resolve, Promise.all, Promise.race, Promise.any, and Promise.allSettled) still assimilate attacker-supplied thenables: native promise resolution performs PromiseResolveThenableJob and invokes the sandboxed code's then method in a microtask without passing through the patched then, so the async restriction is never applied. As a result, sandboxed script can schedule work that runs after VM.run() or NodeVM.run() has returned and outside the configured timeout, continuing to execute after the host believes execution is complete.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · affected: Red Hat Developer Hub, Self-service automation portal 2 · no fix planned: Red Hat Developer Hub, Self-service automation portal 2 · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-92959.json)","depth":"midnight","depthScore":51,"depthScoreParts":{"impact":39.1,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":208790,"id":"CVE-2026-92959","ts":1790024021646,"field":"exploit_available","old":"false","new":"true"}]}