{"id":"CVE-2026-92959","aliases":["GHSA-f8gf-w286-fmq2"],"url":"https://o3.security/vulnerability/CVE-2026-92959","summary":"vm2 before 3.11.8 allowAsync Bypass via Promise Thenable","details":"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, 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.","published":"2026-09-17T13:46:16.252Z","modified":"2026-09-18T03:48:43.341681915Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/92xxx/CVE-2026-92959.json"},{"type":"ADVISORY","url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-f8gf-w286-fmq2"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-92959"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/vm2-before-3.11.8-allowasync-bypass-via-promise-thenable"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-18T03:48:43.341681915Z"}}