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Vulnerability record · CVE-2026-53515 · published 15 July 2026

CVE-2026-53515: Better-auth\/sso improper privilege management vulnerability

Better Auth · Better Auth\/Sso

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.

7.1 CVSS 3.1 High EPSS 0.43% · top 65.7% CWE-269 · Improper privilege managementCWE-285 · Improper authorization
7.1CVSS 3.1 base score
0.43%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
4References
21 Jul 2026Last modified by NVD

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/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/better-auth/better-auth/commit/86765f1597378f5c3deed1b80ca91faac0a6bf00 Patch
https://github.com/better-auth/better-auth/pull/9220 Issue TrackingPatch
https://github.com/better-auth/better-auth/releases/tag/v1.6.11 Release Notes
https://github.com/better-auth/better-auth/security/advisories/GHSA-gv74-j8m3-fg5f MitigationVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.6CVE-2026-53513Better-auth\/sso improper input validation vulnerabilityBetter 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…EPSS 0.25%9.1CVE-2026-53512Better-auth better auth improper authentication vulnerabilityBetter Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, the legacy oidcProvider and mcp plugins expose OAuth toke…EPSS 0.27%8.3CVE-2026-53516Better-auth better auth improper authentication vulnerabilityBetter Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, Better Auth's OAuth callback auto-link gate in handleOAut…EPSS 0.29%8.1CVE-2026-53517Better-auth\/oauth-provider race condition vulnerabilityBetter Auth is an authentication and authorization library for TypeScript. From 1.4.8-beta.7 until 1.6.11, the @better-auth/oauth-provider POST /oaut…EPSS 0.42%7.9CVE-2024-56734Better-auth better auth open redirect vulnerabilityBetter Auth is an authentication library for TypeScript. An open redirect vulnerability has been identified in the verify email endpoint of all versi…EPSS 0.40%7.7CVE-2026-53514Better-auth better auth improper authentication vulnerabilityBetter Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, and in 1.6.14 and later when invitation IDs can be obtain…EPSS 0.20%7.6CVE-2026-53518Better-auth\/oauth-provider race condition vulnerabilityBetter Auth is an authentication and authorization library for TypeScript. From 1.6.0 until 1.6.11, the @better-auth/oauth-provider POST /oauth2/toke…EPSS 0.41%7.6CVE-2026-45337Better-auth better auth improper authorization vulnerabilityBetter Auth is an authentication and authorization library for TypeScript. From 1.6.0 until 1.6.11, the deviceAuthorization plugin treats any authent…EPSS 0.21%

Source: NIST National Vulnerability Database (record CVE-2026-53515), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.