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OpenAdvisories
Medium · 5.9 CVE-2025-71401 EUVD-2025-210592GHSA-3q45-2fh7-66cjGHSA-569q-mpph-wgww

better-auth before 1.4.2 basePath Modification DoS

Published Aug 2, 2026 · Updated Aug 3, 2026 · Assigned by VulnCheck

Description

better-auth (npm) before 1.4.2 allows an external request to configure baseURL when it is not otherwise defined (e.g., BETTER_AUTH_URL is unset). An attacker able to make the very first request to the server after startup can poison the router's base path, causing all routes to return 404 for all users (denial of service). The issue is not reachable when baseURL is explicitly configured or on typical managed hosting platforms.

Affected products

VendorProductAffectedFixed
better-auth better-auth < 1.4.2 1.4.2

Affected packages

EcosystemPackageAffectedFixedRecord
npm better-auth < 1.4.2 1.4.2 GHSA-569q-mpph-wgww

References