Better Auth before 1.4.5 Path Normalization Bypass via rou3 (better-auth better-auth)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.52 % · percentile 44 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- VulnCheck
- NVD status
- Awaiting Analysis
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.
Weaknesses (CWE)
- CWE-20 — Improper Input Validation
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 4.0 | HIGH 8.8 | 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 |
| CVSS 3.1 | HIGH 8.6 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H | VulnCheck |
| CVSS 4.0 | HIGH 8.8 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD · disclosure@vulncheck.com (Secondary) |
| CVSS 3.1 | HIGH 8.6 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H | NVD · disclosure@vulncheck.com (Secondary) |
Advisories
- GHSA-x732-6j76-qmhm — Better Auth's rou3 Dependency has Double-Slash Path Normalization which can Bypass disabledPaths Config and Rate Limits
European references
- ENISA EUVD · EUVD-2025-210590
- GCVE · GCVE-0-2025-71399
Affected products
| Product | Versions |
|---|---|
| better-auth · better-auth | affected 0 < 1.4.5 ; unaffected 1.4.5 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |