CVE-2025-61928

Summary

A critical authentication bypass was identified in the API key creation and update endpoints. An attacker could create or modify API keys for arbitrary users by supplying a victim’s user ID in the request body. Due to a flaw in how the authenticated user was derived, the endpoints could treat attacker-controlled input as an authenticated user object under certain conditions.

Details

The vulnerability originated from fallback logic used when determining the current user. When no session was present, the handler incorrectly allowed request-body data to populate the user context used for authorization decisions. Because server-side validation only executed when authentication was required, privileged fields were not properly protected. As a result, the API accepted unauthenticated requests that targeted other users.

This same pattern affected both the API key creation and update routes.

Impact

Unauthenticated attackers could generate or modify API keys belonging to any user. This granted full authenticated access as the targeted user and, depending on the user’s privileges, could lead to account compromise, access to sensitive data, or broader application takeover.

A critical operation is accessible without requiring any authentication. Typical impact: any user can invoke the privileged function.

CVE-2025-61928 has a CVSS score of 8.6 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.3.26); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2025-61928? CVE-2025-61928 is a high-severity missing authentication for critical function vulnerability in better-auth (npm), affecting versions < 1.3.26. It is fixed in 1.3.26. A critical operation is accessible without requiring any authentication.
2. How severe is CVE-2025-61928? CVE-2025-61928 has a CVSS score of 8.6 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of better-auth are affected by CVE-2025-61928? better-auth (npm) versions < 1.3.26 is affected.
4. Is there a fix for CVE-2025-61928? Yes. CVE-2025-61928 is fixed in 1.3.26. Upgrade to this version or later.
5. Is CVE-2025-61928 exploitable, and should I be worried? Whether CVE-2025-61928 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2025-61928 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2025-61928? Upgrade better-auth to 1.3.26 or later.