CVE-2026-77082

Analyzed Analyzed - Analysis Complete

Regular Expression Denial of Service in n8n Workflow Automation

Publication date: 2026-08-20

Last updated on: 2026-09-01

Assigner: VulnCheck

Description

n8n before 1.123.69, 2.x before 2.33.4, and 2.34.x before 2.34.1 contains a regular expression denial of service (ReDoS) vulnerability in the Filter and Switch nodes, which compile user-supplied regex patterns with new RegExp() and execute them synchronously on the worker thread without complexity validation or execution timeout. A crafted regex pattern can block the worker for an extended period per data item processed, delaying other workflow executions on the same worker.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-20

Last Modified

2026-09-01

Generated

2026-09-09

AI Q&A

2026-08-20

EPSS Evaluated

2026-09-07

NVD

CVE-2026-77082

EUVD

EUVD-2026-63270

Affected Vendors & Products

Vendor	Product	Version / Range
n8n	n8n	to 1.123.69 (exc)
n8n	n8n	From 2.0.0 (inc) to 2.33.4 (exc)
n8n	n8n	2.34.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-1333	The product uses a regular expression with an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles.

Attack-Flow Graph

Executive Summary

This is a Regular Expression Denial of Service (ReDoS) vulnerability in the n8n automation tool affecting versions before 1.123.69, 2.x before 2.33.4, and 2.34.x before 2.34.1. The Filter and Switch nodes compile user-supplied regex patterns using new RegExp() and execute them synchronously on worker threads without complexity validation or execution timeouts. A crafted regex pattern can block the worker thread for an extended period per data item processed, delaying other workflow executions on the same worker.

Detection Guidance

Check n8n version with: n8n --version. If using Docker, run: docker exec <container> n8n --version. Vulnerable versions are before 1.123.69, 2.x before 2.33.4, and 2.34.x before 2.34.1.

Impact Analysis

The vulnerability can reduce system availability by causing worker threads to block for long periods when processing data items with malicious regex patterns. This delays or disrupts other workflow executions on the same worker, potentially impacting performance and operational continuity. The impact requires low privileges and no user interaction.

Compliance Impact

This vulnerability primarily impacts system availability by allowing attackers to disrupt workflow execution through crafted regex patterns. While it does not directly expose data, prolonged service disruptions could interfere with logging, monitoring, or data processing required for compliance. Organizations using affected n8n versions may face challenges meeting availability requirements under GDPR or HIPAA if workflows are critical to data handling processes.

Mitigation Strategies

Upgrade n8n to versions 1.123.69, 2.33.4, or 2.34.1 or later. Restrict instance access to trusted users only. Audit workflows for regex patterns in Filter or Switch nodes.

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