CVE-2026-86076

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

State: Published
Severity: 8.7 High
Published: Sep 8, 2026
Updated: Sep 9, 2026
Reserved: Sep 4, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
4.0	8.7 High	CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:N/SA:N	GitHub_M

Weaknesses

CWE-94 Improper Control of Generation of Code ('Code Injection')

Affected Products

Product	Versions
n8nn8n-io	>= 2.38.0, < 2.38.2Affected >= 2.0.0, < 2.37.7Affected < 1.123.76Affected

References

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