CVE-2026-53513: Better Auth: Server-side request forgery via unvalidated OIDC endpoints on @better-auth/sso provider registration

Description

Better Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, the @better-auth/sso plugin's POST /sso/register and POST /sso/update-provider endpoints accept attacker-controlled oidcConfig.userInfoEndpoint, tokenEndpoint, and jwksEndpoint URLs when skipDiscovery: true is set, store them on the ssoProvider row without origin validation, and fetch them during OIDC callback, allowing non-blind server-side request forgery and possible account linking when trustEmailVerified: true is configured. This issue is fixed in version 1.6.11.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

Attack vector

Network

Complexity

Low

Privileges

Low

User interaction

None

Confidentiality

High

Integrity

High

Availability

None

Scope

Changed

Exploitation

Is it being used?

Exploit prediction (EPSS)0.2% · higher than 16% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

BE

better-auth · better-auth

>= 0.1.0, < 1.6.11 · source: vendor

SS

sso · @better-auth

>= 0.1.0, < 1.6.11 · source: vendor

BA

Better Auth · Better-auth

0.1.0 before 1.6.11 · source: NVD

BE

Better-auth/sso · Better-auth

before 1.6.11 · source: NVD