CVE-2026-86076: n8n: Expression Sandbox Escape via Class-Field Sanitizer Rebinding Can Lead to Code Execution

September 10, 2026

The 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.

References

github.com/advisories/GHSA-hw8v-xxg5-vvvx
github.com/n8n-io/n8n/releases/tag/n8n@1.123.76
github.com/n8n-io/n8n/releases/tag/n8n@2.37.7
github.com/n8n-io/n8n/releases/tag/n8n@2.38.2
github.com/n8n-io/n8n/security/advisories/GHSA-hw8v-xxg5-vvvx
nvd.nist.gov/vuln/detail/CVE-2026-86076

Code Behaviors & Features

Detect and mitigate CVE-2026-86076 with GitLab Dependency Scanning

Secure your software supply chain by verifying that all open source dependencies used in your projects contain no disclosed vulnerabilities. Dependency Scanning using SBOM also detects vulnerabilities from proprietary advisories that this site does not include. Learn more about Dependency Scanning using SBOM →