CVE-2025-71399
Better Auth before 1.4.4 Path Normalization Bypass via rou3
CVSS Score
8.6
EPSS Score
0.0%
EPSS Percentile
0th
Better Auth relies on better-call, which uses the rou3 router library. In affected versions of rou3, paths are normalized by removing empty segments, so /path, //path, and ///path resolve to the same route. In Better Auth versions prior to 1.4.5 (which bundles the fixed rou3), this can allow attackers to bypass disabledPaths configuration and path-based rate limits by submitting requests with extra slashes in the URL path. The issue does not apply in deployments where the proxy or platform normalizes URLs by collapsing multiple slashes.
| CWE | CWE-20 |
| Vendor | better-auth |
| Product | better-auth |
| Published | Aug 2, 2026 |
| Last Updated | Aug 2, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
High
Affected Versions
better-auth / better-auth
0 < 1.4.4
References
github.com: https://github.com/better-auth/better-auth/security/advisories/GHSA-x732-6j76-qmhm github.com: https://github.com/better-auth/better-auth/commit/f60b43fa648399534507c9ac7db36d705b8874c3 vulncheck.com: https://www.vulncheck.com/advisories/better-auth-before-path-normalization-bypass-via-rou3
Credits
🔍 goksan