Better Auth: Privilege escalation via SSO provider registration: missing admin role check in @better-auth/sso
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Privilege escalation, Security bypass
- Confidentiality · integrity · availability
- Low · High · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-269 and CWE-285.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| better-auth | better-auth | 1.2.10 to before 1.6.11 | 1.6.11 | Patch available | CNA |
| better-auth | sso | 1.2.10 to before 1.6.11 | 1.6.11 | Patch available | CNA |
| — | @better-auth/sso (npm) | 1.2.10 to before 1.6.11 | 1.6.11 | Patch available | GHSA-gv74-j8m3-fg5f |
- better-auth Vendorbetter-auth Affected 1.2.10 to before 1.6.11 Fixed in 1.6.11 Patch available CNA
- sso Vendorbetter-auth Affected 1.2.10 to before 1.6.11 Fixed in 1.6.11 Patch available CNA
- @better-auth/sso (npm) Vendor— Affected 1.2.10 to before 1.6.11 Fixed in 1.6.11 Patch available GHSA-gv74-j8m3-fg5f
CPE configurations NVD · 2
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:better-auth:better-auth\/sso:*:*:*:*:*:node.js:*:* | before 1.6.11 | Vulnerable | better-auth |
| cpe:2.3:a:better-auth:better_auth:*:*:*:*:*:node.js:*:* | 1.2.10 to before 1.6.11 | Vulnerable | better-auth |
- cpe:2.3:a:better-auth:better-auth\/sso:*:*:*:*:*:node.js:*:* Versions before 1.6.11 Vulnerable ·better-auth
- cpe:2.3:a:better-auth:better_auth:*:*:*:*:*:node.js:*:* Versions 1.2.10 to before 1.6.11 Vulnerable ·better-auth
Remediation
- Fix · CNA better-auth (better-auth) Fixed in 1.6.11
- Fix · CNA sso (@better-auth) Fixed in 1.6.11
- Fix · GHSA-gv74-j8m3-fg5f @better-auth/sso (npm) Fixed in 1.6.11 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-53515
- 2026-10-03 Alias added: GHSA-gv74-j8m3-fg5f
References
Patch 2
Advisory 2
More Better-auth/sso vulnerabilities
- TI-2026-38587 Better Auth: Server-side request forgery via unvalidated OIDC endpoints on @better-auth/sso provider registration CVSS 3.1CRITICAL 9.6
Sources
- CVE-2026-53515 · CVE Program
- CVE-2026-53515 · NVD
- FIRST EPSS
- GHSA-gv74-j8m3-fg5f · GitHub Advisory Database · CC BY 4.0
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