CVE-2025-71401 — better-auth before 1.4.2 basePath Modification DoS
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 ve…
Published: 2026-08-02 · CVSS: 9.3 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7