{"id":"CVE-2026-86083","aliases":["GHSA-6xcw-7xm6-48c6"],"url":"https://o3.security/vulnerability/CVE-2026-86083","summary":"n8n: Expression Sandbox Escape via Shared Builtin Tampering and Code-Printer Injection Leads to Code Execution","details":"## Impact\n\nTwo stages of expression code generation built source text by calling the global `JSON.stringify` at generation time: the compiler when printing synthetic string literals, and the isolate bridge when interpolating a timezone value into its per-evaluation wrapper. An expression that replaced that global therefore changed the code that was subsequently generated and executed, turning literal data into executable source. The patch renders both code-generation stages through a reference captured at module load, so a later change to global state cannot alter the generated source.\n\nThis vulnerability only affects instances running the legacy expression engine. The `vm` expression engine, which is the default on the patched releases, is not affected.\n\n## Patches\n\nThe issue has been fixed in n8n versions 1.123.76, 2.37.7, and 2.38.2. Users should upgrade to one of these versions or later to remediate the vulnerability.\n\n## Workarounds\n\nIf upgrading is not immediately possible, administrators should consider the following temporary mitigations:\n- Set the environment variable `N8N_EXPRESSION_ENGINE=vm` to switch to the vm expression engine, which is not affected by this vulnerability.\n- Restrict n8n instance access to fully trusted users only.\n- Ensure the n8n process runs under a dedicated low-privilege OS user account to limit the impact of any command execution.\n\nThese workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.","published":"2026-09-08T21:22:40.687Z","modified":"2026-10-21T02:30:24.541968721Z","cvss":null,"epss":{"score":0.0036,"percentile":0.29399,"asOf":"2026-09-15"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"n8n","fixedVersion":"1.123.76"},{"ecosystem":"npm","name":"n8n","fixedVersion":"2.38.2"},{"ecosystem":"npm","name":"n8n","fixedVersion":"2.37.7"}],"fix":null,"references":[{"type":"WEB","url":"https://github.com/n8n-io/n8n/releases/tag/n8n@1.123.76"},{"type":"WEB","url":"https://github.com/n8n-io/n8n/releases/tag/n8n@2.37.7"},{"type":"WEB","url":"https://github.com/n8n-io/n8n/releases/tag/n8n@2.38.2"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/86xxx/CVE-2026-86083.json"},{"type":"ADVISORY","url":"https://github.com/n8n-io/n8n/security/advisories/GHSA-6xcw-7xm6-48c6"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-86083"},{"type":"PACKAGE","url":"https://github.com/n8n-io/n8n"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-21T02:30:24.541968721Z"}}