CVE-2025-61928: Better Auth: Unauthenticated API key creation through api-key plugin
Summary Unauthenticated attackers can create or modify API keys for any user by passing that user's id in the request body to the api/auth/api-key/create route.
Details The vulnerability exists in the authentication logic at when checking for user authentication then derives the user as session?.user ?? (authRequired ? null : { id: ctx.body.userId }). When no session exists but userId is present in the request body, authRequired becomes false and the user object is set to the attacker-controlled ID. Server-only field validation only executes when authRequired is true (lines 280-295), allowing attackers to set privileged fields. No additional authentication occurs before the database operation, so the malicious payload is accepted. The same pattern exists in the update endpoint.
PoC bash curl -X POST http://localhost:3000/api/auth/api-key/create \ -H 'Content-Type: application/json' \ -d '{ "userId": "victim-user-id", "name": "zeropath" }' Response contains the new API key whose userId matches the victim, confirming the bypass.
Impact This is a critical authentication bypass enabling full an unauthenticated attacker can generate an API key for any user and immediately gain complete authenticated access. This allows the attacker to perform any action as the victim user using the api key, potentially compromise the user data and the application depending on the victim's privileges.
This issue was found by ZeroPath.
Other sources
Better Auth is an authentication and authorization library for TypeScript. In versions prior to 1.3.26, unauthenticated attackers can create or modify API keys for any user by passing that user's id in the request body to the api/auth/api-key/create route. session?.user ?? (authRequired ? null : { id: ctx.body.userId }). When no session exists but userId is present in the request body, authRequired becomes false and the user object is set to the attacker-controlled ID. Server-only field validation only executes when authRequired is true (lines 280-295), allowing attackers to set privileged fields. No additional authentication occurs before the database operation, so the malicious payload is accepted. The same pattern exists in the update endpoint. This is a critical authentication bypass enabling full an unauthenticated attacker can generate an API key for any user and immediately gain complete authenticated access. This allows the attacker to perform any action as the victim user using the api key, potentially compromise the user data and the application depending on the victim's privileges. Version 1.3.26 contains a patch for the issue.
— MITRE
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2025-61928?
CVE-2025-61928 is rated as a critical vulnerability due to its potential for unauthenticated API key creation and modification.
How do I fix CVE-2025-61928?
To remediate CVE-2025-61928, users should upgrade to Better Auth version 1.3.26 or later.
Who is affected by CVE-2025-61928?
Users of Better Auth versions prior to 1.3.26 are affected by CVE-2025-61928.
What type of attacks does CVE-2025-61928 allow?
CVE-2025-61928 allows unauthenticated attackers to create or modify API keys for any user.
How can I identify if I am using a vulnerable version regarding CVE-2025-61928?
You can identify if you are using a vulnerable version by checking your Better Auth library version against the affected versions prior to 1.3.26.