CVE-2025-71399
Better Auth before 1.4.5 Path Normalization Bypass via rou3
- State
- Published
- Severity
- 8.8 High
- Published
- Aug 2, 2026
- Updated
- Oct 8, 2026
- Reserved
- Jul 18, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.8 High | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 8.6 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H | VulnCheck |
Weaknesses
- CWE-20 Improper Input Validation
Affected Products
| Product | Versions |
|---|---|
better-authbetter-auth |
|
References
- GitHub Security Advisory (GHSA-x732-6j76-qmhm)vendor-advisory
- Patch Commitpatch
- VulnCheck Advisory: Better Auth before 1.4.4 Path Normalization Bypass via rou3third-party-advisory
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