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). (CVE-2025-71401)
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.
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). (CVE-2025-71401)
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.
CVSS v3.1
Score 5.9medium
Weaknesses
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-3q45-2fh7-66cj
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2025-71401"]
- Ecosystems
- []
- Database Specific Severity
- CRITICAL
- Cvss Version
- 3.1
Threat ID: 6a6fb62cbf32cb7a346e720a
Added to database: 08/02/2026, 21:27:08 UTC
Last updated: 08/02/2026, 21:27:08 UTC
Views: 1
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