CVE-2025-71399: high-severity vulnerability in better-auth
Better Auth before 1.4.5 Path Normalization Bypass via rou3
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.8epss 0.5%
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:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N
Affected products
better-auth · better-authRelated CVEs — better-auth
In the same product, most dangerous first.
CVE-2025-61928CRITICALBetter Auth: Unauthenticated API key creation through api-key pluginEPSS 19.7%CVE-2025-71404MEDIUMbetter-auth before 1.1.16 Reflected XSS via error parameterEPSS 0.7%CVE-2026-67337HIGHbetter-auth before 1.4.9 Two-Factor Authentication Bypass via session.cookieCacheEPSS 0.5%CVE-2025-71401CRITICALbetter-auth before 1.4.2 basePath Modification DoSEPSS 0.5%CVE-2026-67327HIGHbetter-auth before 1.6.22 Account Takeover via Magic-Link Email-OTPEPSS 0.4%CVE-2026-53515HIGHBetter Auth: Privilege escalation via SSO provider registration: missing admin role check in @better-auth/ssoEPSS 0.4%