Vulnerabilities > CVE-2025-27143 - Open Redirect vulnerability in Better-Auth Better Auth

047910
CVSS 6.1 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
LOW
Integrity impact
LOW
Availability impact
NONE
network
low complexity
better-auth
CWE-601
NVD
Published: 2025-02-24
Updated: 2025-02-28

Summary

Better Auth is an authentication and authorization library for TypeScript. Prior to version 1.1.21, the application is vulnerable to an open redirect due to improper validation of the callbackURL parameter in the email verification endpoint and any other endpoint that accepts callback url. While the server blocks fully qualified URLs, it incorrectly allows scheme-less URLs. This results in the browser interpreting the URL as a fully qualified URL, leading to unintended redirection. An attacker can exploit this flaw by crafting a malicious verification link and tricking users into clicking it. Upon successful email verification, the user will be automatically redirected to the attacker's website, which can be used for phishing, malware distribution, or stealing sensitive authentication tokens. This CVE is a bypass of the fix for GHSA-8jhw-6pjj-8723/CVE-2024-56734. Version 1.1.21 contains an updated patch.

Vulnerable Configurations

Part Description Count
Application
Better-Auth
1

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Fake the Source of Data
    An adversary provides data under a falsified identity. The purpose of using the falsified identity may be to prevent traceability of the provided data or it might be an attempt by the adversary to assume the rights granted to another identity. One of the simplest forms of this attack would be the creation of an email message with a modified "From" field in order to appear that the message was sent from someone other than the actual sender. Results of the attack vary depending on the details of the attack, but common results include privilege escalation, obfuscation of other attacks, and data corruption/manipulation.

References