Vulnerability 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.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/better-auth/better-auth/commit/f60b43fa648399534507c9ac7db36d
- https://github.com/better-auth/better-auth/security/advisories/GHSA-x732-6j76-qm
- https://www.vulncheck.com/advisories/better-auth-before-path-normalization-bypas
FAQ
What is CVE-2025-71399?
CVE-2025-71399 is a vulnerability with a CVSS score of 8.6 (HIGH). 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 ...
How severe is CVE-2025-71399?
CVE-2025-71399 has been rated HIGH with a CVSS base score of 8.6/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2025-71399?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.