{"id":"GHSA-6xcw-7xm6-48c6","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.","aliases":["CVE-2026-86083"],"modified":"2026-09-10T20:45:04.270557769Z","published":"2026-09-10T20:37:21Z","database_specific":{"nvd_published_at":"2026-09-08T22:19:17Z","cwe_ids":["CWE-94"],"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-09-10T20:37:21Z"},"references":[{"type":"WEB","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"},{"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"}],"affected":[{"package":{"name":"n8n","ecosystem":"npm","purl":"pkg:npm/n8n"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.123.76"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-6xcw-7xm6-48c6/GHSA-6xcw-7xm6-48c6.json"}},{"package":{"name":"n8n","ecosystem":"npm","purl":"pkg:npm/n8n"},"ranges":[{"type":"SEMVER","events":[{"introduced":"2.38.0"},{"fixed":"2.38.2"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-6xcw-7xm6-48c6/GHSA-6xcw-7xm6-48c6.json"}},{"package":{"name":"n8n","ecosystem":"npm","purl":"pkg:npm/n8n"},"ranges":[{"type":"SEMVER","events":[{"introduced":"2.0.0"},{"fixed":"2.37.7"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-6xcw-7xm6-48c6/GHSA-6xcw-7xm6-48c6.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"}]}