Better Auth

An Insecure Direct Object Reference (IDOR) vulnerability (CVE-2025-71400) in better-auth passkey versions before 1.4.0 allows authenticated users to delete arbitrary passkeys by enumerating IDs.

Better Auth versions prior to 1.4.5 contain a path normalization vulnerability in the rou3 library that allows attackers to bypass disabledPaths configurations and rate limits via URL path manipulation.

The better-auth library fails to validate redirect_uri schemes in its oidc-provider and mcp plugins, allowing attackers to inject javascript: URIs that lead to XSS and potential account takeover.

An authorization bypass vulnerability in better-auth SCIM (CVE-2026-67331) allows authenticated users to manage and manipulate SCIM providers belonging to other users due to missing owner-binding checks.

An authorization bypass vulnerability in @better-auth/stripe allows authenticated users to perform unauthorized subscription actions and access billing data of other organizations via ID parameter confusion.

Multiple authentication bypass vulnerabilities in @better-auth/sso allow attackers to perform account takeovers by exploiting flaws in SSO provider handling.

The better-auth library is vulnerable to account takeover (CVE-2026-67327) when open email/password registration is enabled, allowing attackers to maintain persistent access after a victim authenticates via passwordless flows.

An authorization bypass vulnerability in the `@better-auth/stripe` library allows authenticated users to perform subscription actions (cancel, change plan, restore, open billing portal) against other organizations they are a member of, but not authorized to manage. This occurs due to inconsistent handling of organization IDs between the middleware, which approves the ID from the request query string, and the route handler, which acts on the active organization ID from the session or request body. This flaw enables users to access sensitive billing details and manipulate subscriptions for unintended organizations.

The `@better-auth/scim` package is affected by multiple vulnerabilities, including a critical provider-ID collision flaw that allows authenticated users to craft SCIM tokens impersonating existing account providers, leading to unauthorized account access, profile modification, and user deletion, while additional issues include failed user deactivation and email update vulnerabilities bypassing uniqueness checks in versions `1.4.0-beta.27` through `1.6.21` and `1.7.0-beta.0` through `1.7.0-beta.9`.

A high-severity authorization bypass vulnerability (CVE-2026-53515) in `@better-auth/sso` versions `>= 1.2.10, < 1.6.11` allows regular organization members to register new SSO providers for an organization, potentially leading to unauthorized user creation and, under specific configurations, unauthorized administrative access within the target organization.

The legacy `oidcProvider` and `mcp` plugins in the `better-auth` library versions prior to 1.6.11 are vulnerable to CVE-2026-53512, an OAuth refresh-token replay attack where the plugins fail to verify the `client_secret` of confidential clients during the `refresh_token` grant, allowing an attacker who obtains a valid `refresh_token` and `client_id` to indefinitely mint new access tokens and impersonate the client for unauthorized resource access.