CVE-2026-53515: 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
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.
Details
Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-53515
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-535150.24% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 15% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-53515 | coverage & exploitation status | NVD · CVE.org |
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