CVE-2025-71399Network attack vectorHinoki check available

Protection bypass via discarded empty path segments

Published Aug 2, 2026 · Updated Aug 2, 2026

Path normalization bypass in Better Auth before 1.4.5 allows remote attackers to evade disabled paths and path-based rate limits. The rou3 splitPath function removes empty segments from request paths, causing /path, //path, and ///path to resolve to the same route. Exploitation requires a deployment that forwards repeated slashes unchanged; the result is access to disabled endpoints or evasion of request throttling.

CVSS severity8.8
High
EPSS probability0.31%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Path normalization bypass in Better Auth before 1.4.5 allows remote attackers to evade disabled paths and path-based rate limits. The rou3 splitPath function removes empty segments from request paths, causing /path, //path, and ///path to resolve to the same route. Exploitation requires a deployment that forwards repeated slashes unchanged; the result is access to disabled endpoints or evasion of request throttling.

The record

CVE
CVE-2025-71399
Published
Aug 2, 2026
Updated
Aug 2, 2026
Vendor
Better Auth
Product
Better Auth
Classifications
CWE-20, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <1.4.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Better Auth · Better Authversion=0 <1.4.4

Published CVSS scores

8.6VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
8.8VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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