CVE-2025-71401
better-auth before 1.4.2 basePath Modification DoS
- State
- Published
- Severity
- 9.3 Critical
- Published
- Aug 2, 2026
- Updated
- Aug 3, 2026
- Reserved
- Jul 18, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 9.3 Critical | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 5.9 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H | VulnCheck |
Weaknesses
- CWE-770 Allocation of Resources Without Limits or Throttling
Affected Products
| Product | Versions |
|---|---|
better-authbetter-auth |
|
References
- GitHub Security Advisory (GHSA-569q-mpph-wgww)vendor-advisory
- VulnCheck Advisory: better-auth before 1.4.1 basePath Modification DoSthird-party-advisory
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