What’s Vulnerable › Vulnerabilities

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

• Severity: critical (CVSS 9.6 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-15 · updated 2026-07-21
• Weakness: CWE-20

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.

Affected products

• Better-Auth/Sso: before 1.6.11 — fixed in 1.6.11
• better-auth: from 0.1.0 before 1.6.11 — fixed in 1.6.11

How to fix

Upgrade to a fixed version: Better-Auth/Sso 1.6.11; better-auth 1.6.11. Check the vendor advisory for mitigations.

References

• https://github.com/better-auth/better-auth/commit/37f60cb176cb53147da7dfd5ec15afa5b486e81e
• https://github.com/better-auth/better-auth/pull/9574
• https://github.com/better-auth/better-auth/releases/tag/v1.6.11
• https://github.com/better-auth/better-auth/security/advisories/GHSA-5rr4-8452-hf4v

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