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22Track

n8n: Expression Sandbox Escape in Editor-UI Enables Stored Cross-User JavaScript Execution

n8n · CVE-2026-86076
0 news outlets1 CERTs and agencies0 research labs

Assessment: Track

SSVC decision points: exploitation poc, automatable no, technical impact total, deployment medium.

What is it?

n8n is an open source workflow automation platform. Prior to 1.123.76, 2.37.7, and 2.38.2, the expression compiler sanitizer resolved through dynamically scoped this and did not reject reserved class member names. A class field named __sanitize could rebind the sanitizer and reach the Function constructor, enabling backend code execution and editor-preview JavaScript execution. The affected AST hook is PrototypeSanitizer in packages/workflow/src/expression-sandboxing.ts. This issue is fixed in versions 1.123.76, 2.37.7 and 2.38.2.

Evidence

Official warnings1National CERTs, government cyber security agencies and the vendor’s own advisories

Exploitation

  • Exploit code published (not verified by us)
  • Exploited in the wild (confirmed by a source)
  • Listed as known exploited (CISA KEV)
CVSS
8.7
EPSS
0.8%
First seen
9 h ago
Status
confirmed

All n8n vulnerabilities