Authentication Bypass in n8n Workflow Automation

Executive Summary

The vulnerability CVE-2026-54308 affects the n8n workflow automation platform in versions prior to 2.25.7 and 2.26.2. Specifically, the MicrosoftAgent365Trigger and StripeTrigger nodes did not validate inbound requests properly. This means an unauthenticated attacker who knows the webhook URL can submit forged payloads, causing the workflow to execute with attacker-controlled data.

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Compliance Impact

The vulnerability allows unauthenticated attackers to submit forged payloads to webhook URLs and execute workflows with attacker-controlled data. This could lead to unauthorized processing or exposure of sensitive data within the affected workflows.

Such unauthorized access and manipulation of data may impact compliance with standards and regulations like GDPR and HIPAA, which require strict controls over data integrity, confidentiality, and access.

Remediation by upgrading to fixed versions or applying mitigations is necessary to maintain compliance and reduce risk.

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Detection Guidance

This vulnerability involves unauthenticated requests to the MicrosoftAgent365Trigger and StripeTrigger webhook URLs in n8n versions prior to 2.25.7 and 2.26.2. Detection can focus on monitoring inbound HTTP requests to these webhook endpoints for suspicious or forged payloads.

Suggested detection steps include:

• Check your n8n instance version to confirm if it is vulnerable (versions before 2.25.7 or 2.26.2).
• Monitor web server or application logs for unexpected or unauthenticated POST requests to the MicrosoftAgent365Trigger and StripeTrigger webhook URLs.
• Use network traffic analysis tools (e.g., tcpdump, Wireshark) to capture and inspect HTTP requests targeting the webhook endpoints.
• Example command to check logs for suspicious webhook calls (assuming logs contain webhook URL paths):
• grep -i 'microsoftagent365trigger\|stripetrigger' /path/to/n8n/logs/*
• Example tcpdump command to capture HTTP POST requests to the webhook endpoint (replace <webhook_path> with actual path):
• sudo tcpdump -A -s 0 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)' | grep 'POST /<webhook_path>'

Since the vulnerability is due to missing token validation, any unauthenticated POST requests to these webhook URLs should be considered suspicious.

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Impact Analysis

This vulnerability allows an unauthenticated attacker to bypass authentication by submitting forged payloads to webhook URLs. As a result, the attacker can trigger workflows with malicious or manipulated data, potentially leading to unauthorized actions or data manipulation within the affected system.

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Mitigation Strategies

To mitigate the vulnerability CVE-2026-54308 in n8n, you should upgrade to versions 2.25.7 or 2.26.2 or later.

As temporary mitigations before upgrading, you can deactivate the affected workflows or restrict network access to the webhook endpoints to prevent unauthenticated attackers from submitting forged payloads.

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