{"id":"CVE-2026-86076","aliases":["GHSA-hw8v-xxg5-vvvx"],"url":"https://o3.security/vulnerability/CVE-2026-86076","summary":"n8n: Expression Sandbox Escape in Editor-UI Enables Stored Cross-User JavaScript Execution","details":"## Impact\n\nThe expression compiler's sanitizer resolved through a dynamically-scoped `this`, so a class field named `__sanitize` rebound it and reached the `Function` constructor. On the backend, any expression author could run code in the n8n process; in the editor preview, a member's expression could run as JavaScript in the session of whoever opened the workflow. The patch rejects reserved class-member names.\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- Restrict n8n instance access to fully trusted users only.\n- Avoid granting workflow-create or workflow-edit permissions to untrusted users.\n- Audit existing workflows for unexpected or unfamiliar expressions in node parameters.\n- Set `N8N_EXPRESSION_ENGINE=vm`.\n\nThese workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.","published":"2026-09-08T21:28:52.762Z","modified":"2026-10-21T02:30:16.351180631Z","cvss":null,"epss":{"score":0.00429,"percentile":0.36526,"asOf":"2026-09-16"},"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-2026-86076.json"},{"type":"ADVISORY","url":"https://github.com/n8n-io/n8n/security/advisories/GHSA-hw8v-xxg5-vvvx"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-86076"},{"type":"PACKAGE","url":"https://github.com/n8n-io/n8n"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-21T02:30:16.351180631Z"}}