CVE-2026-53515
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.43%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.1 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N
- EPSS
- 0.43% probability · 36th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-269, CWE-285, CWE-863
- Affected
- better-auth/better-auth\/sso · better-auth/better auth
- Source
- security-advisories@github.com
References
- https://github.com/better-auth/better-auth/commit/86765f1597378f5c3deed1b80ca91faac0a6bf00Patch
- https://github.com/better-auth/better-auth/pull/9220Issue Tracking, Patch
- https://github.com/better-auth/better-auth/releases/tag/v1.6.11Release Notes
- https://github.com/better-auth/better-auth/security/advisories/GHSA-gv74-j8m3-fg5fMitigation, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.