CVE-2025-71399Better Auth before 1.4.5 Path Normalization Bypass via rou3
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No exploitation reported and no EPSS estimate yet.
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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
- 8.6 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
- Weakness (CWE)
- CWE-20
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- VulnCheck
- NVD analysis
- Awaiting Analysis
- Record last updated
- Oct 8, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
better-auth better-auth better_auth:better_auth (from the name) | before 1.4.5; 1.4.5 not affected | CNA record |
References
- https://github.com/better-auth/better-auth/security/advisories/GHSA-x732-6j76-qmhmvendor-advisory
- https://github.com/better-auth/better-auth/commit/f60b43fa648399534507c9ac7db36d705b8874c3patch
- https://www.vulncheck.com/advisories/better-auth-before-path-normalization-bypass-via-rou3third-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.