What’s Vulnerable › Vulnerabilities

CVE-2026-110842: n8n before 2.41.4 and 2.42.1 Prototype Pollution via MCP Workflow-Validation Interpreter

• Severity: high (CVSS 7.7 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-14 · updated 2026-10-15
• Weakness: CWE-1321

Description

n8n before 2.41.4 and 2.42.x before 2.42.1 contains a prototype pollution vulnerability in the MCP workflow-validation tool, whose interpreter evaluates caller-supplied code in the main process, reads inherited properties, and permits assignment onto shared prototypes. An authenticated member holding only a workflow:read grant can replace a built-in method with one returning a truthy value so server-side permission checks accept unheld scopes, enabling takeover of owner accounts not protected by MFA.

Affected products

• n8n-io n8n: before 2.41.4; from 2.42.0 before 2.42.1 — fixed in 2.41.4, 2.42.1

How to fix

Upgrade to a fixed version: n8n-io n8n 2.41.4, 2.42.1. Check the vendor advisory for mitigations.

References

• https://github.com/n8n-io/n8n/security/advisories/GHSA-5jr4-xmvf-frmj
• https://www.vulncheck.com/advisories/n8n-before-2.41.4-and-2.42.1-prototype-pollution-via-mcp-workflow-validation-interpreter

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