CVE-2026-31882

Received Received - Intake

Authentication Bypass in Dagu SSE Endpoints Exposes Sensitive Data

Publication date: 2026-03-13

Last updated on: 2026-03-18

Assigner: GitHub, Inc.

Description

Dagu is a workflow engine with a built-in Web user interface. Prior to 2.2.4, when Dagu is configured with HTTP Basic authentication (DAGU_AUTH_MODE=basic), all Server-Sent Events (SSE) endpoints are accessible without any credentials. This allows unauthenticated attackers to access real-time DAG execution data, workflow configurations, execution logs, and queue status — bypassing the authentication that protects the REST API. The buildStreamAuthOptions() function builds authentication options for SSE/streaming endpoints. When the auth mode is basic, it returns an auth.Options struct with BasicAuthEnabled: true but AuthRequired defaults to false (Go zero value). The authentication middleware at internal/service/frontend/auth/middleware.go allows unauthenticated requests when AuthRequired is false. This vulnerability is fixed in 2.2.4.

CVSS Scores

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Meta Information

Published

2026-03-13

Last Modified

2026-03-18

Generated

2026-07-06

AI Q&A

2026-03-13

EPSS Evaluated

2026-07-05

NVD

CVE-2026-31882

EUVD

EUVD-2026-12087

Affected Vendors & Products

Vendor	Product	Version / Range
dagu	dagu	to 2.2.4 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-306	The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

Attack-Flow Graph

Executive Summary

This vulnerability exists in Dagu, a workflow engine with a built-in Web user interface. Before version 2.2.4, when Dagu is set to use HTTP Basic authentication, all Server-Sent Events (SSE) endpoints can be accessed without requiring any credentials.

This means that unauthenticated attackers can bypass the authentication protecting the REST API and gain access to sensitive real-time data such as DAG execution data, workflow configurations, execution logs, and queue status.

The root cause is that the authentication middleware allows unauthenticated requests to SSE endpoints because the AuthRequired flag defaults to false, even when BasicAuthEnabled is true. This issue was fixed in version 2.2.4.

Impact Analysis

This vulnerability can allow attackers to access sensitive and real-time workflow execution data without authentication.

Exposure of DAG execution data
Access to workflow configurations
Viewing execution logs
Monitoring queue status

Such unauthorized access could lead to information disclosure and potentially aid attackers in further exploiting the system.

Compliance Impact

I don't know

Detection Guidance

I don't know

Mitigation Strategies

To mitigate this vulnerability, upgrade Dagu to version 2.2.4 or later, where the issue is fixed.

Avoid using HTTP Basic authentication (DAGU_AUTH_MODE=basic) with versions prior to 2.2.4, as SSE endpoints are accessible without credentials in those versions.

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