CVE-2025-71399 Better Auth before 1.4.5 Path Normalization Bypass via rou3

Better Auth relies on better-call, which uses the rou3 router library. In affected versions of rou3, paths are normalized by removing empty segments, so /path, //path, and ///path resolve to the same route. In Better Auth versions prior to 1.4.5 which bundles the fixed rou3, this can allow...

CVE-2025-71399

Better Auth relies on better-call, which uses the rou3 router library. In affected versions of rou3, paths are normalized by removing empty segments, so /path, //path, and ///path resolve to the same route. In Better Auth versions prior to 1.4.5 which bundles the fixed rou3, this can allow...

CVE-2025-71404

better-auth versions after v0.0.2 and before 1.1.16 contain a reflected cross-site scripting XSS vulnerability on the /api/auth/error page, where the value of the 'error' URL parameter is reflected as HTML without proper neutralization. An attacker who coerces a user into visiting a...

CVE-2026-67337

CVE-2026-67337 affects better-auth versions before 1.4.9. The issue is a two‑factor authentication bypass when session.cookieCache is enabled: attackers with valid primary credentials can reach authenticated routes without completing second‑factor verification by exploiting premature session cach...

CVE-2026-67336

CVE-2026-67336 affects better-auth versions before 1.6.11, specifically the oidcProvider and mcp plugins. The root cause is insecure cryptographic defaults that advertise the none algorithm and allow plain PKCE by default. This can enable an attacker to exploit algorithm negotiation to accept uns...

CVE-2025-71403 better-auth before 1.1.20 Open Redirect via trustedOrigins Bypass

better-auth versions before 1.1.20 contain a bypass vulnerability in trustedOrigins validation logic affecting absolute URLs and wildcard domains. Attackers can construct malicious callbackURL parameters that pass origin checks and trigger open redirects to steal sensitive tokens for account...

CVE-2026-67334 better-auth Stale Sessions Persist After User Deletion

better-auth versions before 1.6.11 fail to delete cached sessions when removing users via admin, anonymous, or SCIM endpoints when secondaryStorage is configured and storeSessionInDatabase is false. Attackers can reuse deleted user session tokens to maintain authentication for up to seven days...

CVE-2026-67336 better-auth before 1.6.11 Insecure Cryptographic Defaults via oidcProvider

better-auth versions before 1.6.11 contain insecure cryptographic defaults in the oidcProvider and mcp plugins that advertise the none algorithm and accept plain PKCE by default. Attackers can exploit algorithm negotiation to accept unsigned tokens or intercept authorization codes when PKCE plain...

EUVD-2025-210582

better-auth versions before 1.1.20 contain a bypass vulnerability in trustedOrigins validation logic affecting absolute URLs and wildcard domains. Attackers can construct malicious callbackURL parameters that pass origin checks and trigger open redirects to steal sensitive tokens for account...

CVE-2025-71403 better-auth before 1.1.20 Open Redirect via trustedOrigins Bypass

better-auth versions before 1.1.20 contain a bypass vulnerability in trustedOrigins validation logic affecting absolute URLs and wildcard domains. Attackers can construct malicious callbackURL parameters that pass origin checks and trigger open redirects to steal sensitive tokens for account...

CVE-2026-67335 better-auth before 1.6.2 OAuth State Validation Bypass

better-auth versions before 1.6.2 fail to validate the OAuth state parameter against the stored nonce when using cookie-backed state storage without PKCE. Attackers can forge the state parameter and supply an attacker-controlled authorization code to create authenticated sessions bound to the...

CVE-2025-71404

Summary: CVE-2025-71404 affects better-auth versions after 0.0.2 and before 1.1.16. The vulnerability is a reflected XSS on the /api/auth/error page where the URL parameter error is echoed into HTML without proper neutralization, enabling arbitrary JavaScript when a user visits a crafted link. Im...

EUVD-2026-51839

@better-auth/sso versions before 1.6.21 contain multiple authentication bypass vulnerabilities in SSO provider handling that allow attackers to sign in as arbitrary users. Attackers can exploit domain verification parsing mismatches, orphaned provider accounts, unbound SAML assertions, or reflect...

CVE-2026-67327

Better-Auth before 1.6.22 is vulnerable to account takeover via pre-account hijacking on magic-link and email-OTP sign-in when open email/password registration is enabled. An attacker registers a victims email with a chosen password; the account remains unverified. When the victim signs in later...

CVE-2026-67330 better-auth SCIM 1.4.0-beta.27 through 1.6.21 Account Takeover via Provider-ID Collision

@better-auth/scim a better-auth plugin versions = 1.4.0-beta.27 through = 1.7.0-beta.0 through = 1.7.0-beta.9 contain an authorization bypass. SCIM token issuance did not reject provider IDs already used by existing SSO, SAML, OIDC, generic OAuth, or social account providers, and the same logical...

EUVD-2025-210584

better-auth versions greater than 1.3.34 and before 1.4.0 contain a vulnerability in the multi-session plugin's /sign-out after-hook, which trusts raw multi-session cookies and forwards extracted values to internalAdapter.deleteSessions without verifying the cookie signature e.g., via...

CVE-2025-71402 better-auth before 1.4.0 Session Revocation via Forged Cookie

better-auth versions greater than 1.3.34 and before 1.4.0 contain a vulnerability in the multi-session plugin's /sign-out after-hook, which trusts raw multi-session cookies and forwards extracted values to internalAdapter.deleteSessions without verifying the cookie signature e.g., via...

Incorrect Authorization

Overview @better-auth/sso is a SSO plugin for Better Auth Affected versions of this package are vulnerable to Incorrect Authorization via the POST /sso/register endpoint, which allows any organization member to attach a new SSO provider without verifying admin or owner privileges. An attacker can...

CVE-2026-53514

Better 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 obtained outside the invited mailbox and requireEmailVerificationOnInvitation: true is not enabled, the organization plugin's acceptInvitation,...

CVE-2026-53517 Better Auth OAuth Provider: Refresh Token Rotation Race Condition Allows Concurrent Replay and Token Family Forking

Better 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 /oauth2/token endpoint on the refreshtoken grant performs a non-atomic read, validate, revoke, and mint sequence on the oauthRefreshToken row, allowing...