Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2026-41427

Severity CVSS v4.0:
HIGH
Type:
Unavailable / Other
Publication date:
24/04/2026
Last modified:
13/05/2026

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.

Impact

Vector 4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:L/SA:N CVSS v4.0 Severity and Metrics:

Base Score: 7.10 HIGH
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:L/SA:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): None
Privileges Required (PR): Low
User Interaction (UI): None
Confidentiality (VC): None
Integrity (VI): High
Availability (VA): None
Confidentiality (SC): None
Integrity (SI): Low
Availability (SA): None

Base Score 4.0
7.10
Severity 4.0
HIGH
Vector 3.x
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N CVSS v3.1 Severity and Metrics:

Base Score: 6.50 MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): High
Availability (A): None

Base Score 3.x
6.50
Severity 3.x
MEDIUM

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:better-auth:better-auth\/oauth-provider:*:*:*:*:*:node.js:*:* 1.4.9 (including) 1.6.5 (excluding)
cpe:2.3:a:better-auth:better-auth\/oauth-provider:1.4.8:-:*:*:*:node.js:*:*
cpe:2.3:a:better-auth:better-auth\/oauth-provider:1.4.8:beta7:*:*:*:node.js:*:*
cpe:2.3:a:better-auth:better-auth\/oauth-provider:1.7.0:beta0:*:*:*:node.js:*:*

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools