9.9

CVSS Score

3.1

-

CVSS Score

Basic Information

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CVE-2026-1470

CVE-2026-1470: n8n Unsafe Workflow Expression Evaluation Allows Remote Code Execution

n8n contains a critical Remote Code Execution (RCE) vulnerability in its workflow Expression evaluation system. Expressions supplied by authenticated users during workflow configuration may be evaluated in an execution context that is not sufficiently isolated from the underlying runtime.

An authenticated attacker could abuse this behavior to execute arbitrary code with the privileges of the n8n process. Successful exploitation may lead to full compromise of the affected instance, including unauthorized access to sensitive data, modification of workflows, and execution of system-level operations.

(GitHub Advisory)

Miggo Vulnerability Database

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CVE-2026-1470

CVE-2026-1470:

9.9

CVSS Score

3.1

-

CVSS Score

Basic Information

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Technical Details

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
n8n	npm	< 1.123.17	1.123.17
n8n	npm	>= 2.0.0, < 2.4.5	2.4.5
n8n	npm	>= 2.5.0, < 2.5.1	2.5.1

Technical Details

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The vulnerability is a Remote Code Execution (RCE) in n8n's expression evaluation mechanism, caused by an insufficient sandbox. The analysis of the provided patches shows that the core of the fix lies in the PrototypeSanitizer function located in packages/workflow/src/expression-sandboxing.ts.

This function operates on the Abstract Syntax Tree (AST) of the user-provided expression to detect and remove potentially malicious code before it gets executed. The patches harden this function by adding new security controls:

Disallowing with statements: A visitWithStatement method was added to the AST visitor within PrototypeSanitizer. This method throws an error whenever a with statement is encountered. The with statement in JavaScript can be abused to manipulate the scope chain, which was the vector for the RCE in this case. The test cases added in the patch confirm this with an exploit payload.
Preventing variable shadowing: The patch introduces checks within visitVariableDeclarator, visitFunction, and visitCatchClause to prevent the declaration of variables with reserved names like ___n8n_data and __sanitize. This prevents attackers from overwriting critical variables used by the sandboxing environment itself.

Before these changes, the PrototypeSanitizer function was inadequate, allowing malicious expressions to pass through the sandbox, leading to the RCE. Therefore, PrototypeSanitizer is the key function that was modified to mitigate the vulnerability and would be present in the execution stack when a malicious expression is evaluated.

Vulnerable functions

PrototypeSanitizer

packages/workflow/src/expression-sandboxing.ts

This function is an AST hook responsible for sanitizing expressions before execution. Prior to the patch, it lacked checks for `with` statements and the shadowing of reserved variables. This allowed an attacker to craft a malicious expression that could bypass the sandbox and achieve Remote Code Execution. The patch adds visitors like `visitWithStatement` to this function to detect and block such malicious patterns.

Vulnerability Intelligence
Miggo AI

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WAF Protection Rules

WAF Rule

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Reasoning

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