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CVE-2025-71399

Better Auth before 1.4.5 Path Normalization Bypass via rou3

Published: Aug 2, 2026Updated: Aug 3, 2026 Sources: CVE List NVDCWE-20
8.6HIGH
NVD MITRE
EPSS Score
0.3%
Top 77.1%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available
Self-Check
Not available

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:LI:LA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:LConfidentiality
Low
I:LIntegrity
Low
A:HAvailability
High
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Weaknesses

CWE-20

Affected Products

better-auth
oss-projectaka better auth
better-authLibrary
OSS Libraries / web-framework

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Initial Access
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References

https://github.com/better-auth/better-auth/commit/f60b43fa648399534507c9ac7db36d705b8874c3
github.com
https://github.com/better-auth/better-auth/security/advisories/GHSA-x732-6j76-qmhm
github.com
https://www.vulncheck.com/advisories/better-auth-before-path-normalization-bypass-via-rou3
vulncheck.com

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