CVE-2026-77082
Received Received - Intake

Regular Expression Denial of Service in n8n Workflow Automation

Publication date: 2026-08-20

Last updated on: 2026-08-20

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.

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Meta Information

Published
2026-08-20
Last Modified
2026-08-20
Generated
2026-08-20
AI Q&A
2026-08-20
EPSS Evaluated
N/A
NVD
CVE-2026-77082
EUVD
EUVD-2026-63270

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
n8n n8n to 1.123.69 (exc)
n8n n8n to 2.33.4 (exc)
n8n n8n to 2.34.1 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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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

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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.

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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