{"id":"CVE-2026-93603","state":"PUBLISHED","title":"vm2 before 3.12.1 Sandbox Escape RCE via Non-Strict Host Function","description":"vm2 through 3.12.0 (fixed in 3.12.1) does not correctly handle a nullish `this` receiver in the apply trap of its bridge (lib/bridge.js): when sandboxed code calls a host-provided non-strict (sloppy-mode) function without a receiver — e.g. `fn()`, a detached method, `fn.call()`, `fn.apply(undefined)`, `Reflect.apply(fn, undefined, [])`, or `fn.bind()()` — the undefined receiver is passed straight through to the host call, and V8 substitutes the host realm's global object for `this`. vm2 then wraps and returns that object to the sandbox, giving sandboxed script a live proxy of the host global. This allows a complete sandbox escape: untrusted script can reach `process` and execute arbitrary code/commands on the host (for example via `process.getBuiltinModule('child_process').execSync`). Exploitation requires that the embedding application expose at least one non-strict host function to the sandbox; strict-mode and ES module host functions are not affected.","publishedAt":"2026-09-18T13:20:12.955Z","updatedAt":"2026-09-22T14:25:29.801Z","severity":{"score":10,"label":"Critical","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H","source":"VulnCheck"},"assigner":"VulnCheck","products":["patriksimek vm2"],"affected":[{"vendor":"patriksimek","product":"vm2","packageURL":"pkg:npm/vm2","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"3.12.1","versionType":"semver"},{"version":"3.12.1","status":"unaffected","versionType":"semver"}]}],"references":["https://github.com/patriksimek/vm2/security/advisories/GHSA-j89j-5m6r-cr2q","https://www.vulncheck.com/advisories/vm2-before-3.12.1-sandbox-escape-rce-via-non-strict-host-function"],"weaknesses":["CWE-94"],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/93xxx/CVE-2026-93603.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-93603","state":"PUBLISHED","datePublished":"2026-09-18T13:20:12.955Z","dateUpdated":"2026-09-22T14:25:29.801Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-09-18T11:00:32.756Z"},"containers":{"cna":{"title":"vm2 before 3.12.1 Sandbox Escape RCE via Non-Strict Host Function","descriptions":[{"lang":"en","value":"vm2 through 3.12.0 (fixed in 3.12.1) does not correctly handle a nullish `this` receiver in the apply trap of its bridge (lib/bridge.js): when sandboxed code calls a host-provided non-strict (sloppy-mode) function without a receiver — e.g. `fn()`, a detached method, `fn.call()`, `fn.apply(undefined)`, `Reflect.apply(fn, undefined, [])`, or `fn.bind()()` — the undefined receiver is passed straight through to the host call, and V8 substitutes the host realm's global object for `this`. vm2 then wraps and returns that object to the sandbox, giving sandboxed script a live proxy of the host global. 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