Medium severity · published Apr 24, 2026
CVE-2026-41427
Better Auth OAuth 2.1 Provider: Unprivileged users can register OAuth clients
6.5
CVSS
0.2%
EPSS
No
On KEV
Description
Better Auth is an authentication and authorization library for TypeScript. Prior to 1.6.5, the clientPrivileges option documents a create action, but the OAuth client creation endpoints did not invoke the hook before persisting new clients. Deployments that configured clientPrivileges to restrict client registration were not actually restricted — any authenticated user could reach the create endpoints and register an OAuth client with attacker-chosen redirect URIs and metadata. This vulnerability is fixed in 1.6.5.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 11% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
BE
better-auth · better-auth
>= 1.4.8-beta.7, < 1.6.5; >= 1.7.0-beta.0, <= 1.7.0-beta.1 · source: vendor
OA
oauth-provider · better-auth
>= 1.4.8-beta.7, < 1.6.5; >= 1.7.0-beta.0, <= 1.7.0-beta.1 · source: vendor
BE
Better-auth/oauth-provider · Better-auth
1.4.9 before 1.6.5; 1.4.8; 1.4.8; 1.7.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-41427
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-41427
Mitigation
https://github.com/better-auth/better-auth/security/advisories/GHSA-xr8f-h2gw-9xh6
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