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...

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-2025-71404

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...

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-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...

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-2026-67330 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-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...

CVE-2026-53514

Better Auth (organization plugin) exposes a vulnerability where an attacker with an unverified session for the invited email and a leaked invitationId can join the organization by calling acceptInvitation/rejectInvitation/getInvitation/listUserInvitations, due to email-string ownership checks not...

CVE-2026-53515

CVE-2026-53515 : The Better Auth library, specifically the @better-auth/sso plugin, contains a privilege escalation in versions 1.2.10 through 1.6.11. The POST /sso/register endpoint incorrectly allows any organization member to attach a new SSO provider because registerSSOProvider checks only fo...

CVE-2026-53512 Better Auth: OAuth refresh-token replay via missing client authentication on oidc-provider and mcp plugins

Better Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, the legacy oidcProvider and mcp plugins expose OAuth token endpoints whose refreshtoken grant authenticates only possession of the bound refreshToken row and matching clientid, without verifying the...

NPM: Better Auth: OAuth refresh-token replay via missing client authentication on oidc-provider and mcp plugins

NPM: Better Auth: OAuth refresh-token replay via missing client authentication on oidc-provider and mcp plugins vulnerability discovered by ? in WordPress Npm better-auth versions 1.6.11...

EUVD-2026-33073

Better Auth is an authentication and authorization library for TypeScript. Prior to 1.4.17 and 1.5.0-beta.9, Better Auth's HTTP rate limiter keyed each request by the exact textual IP address it received in x-forwarded-for or the configured IP-bearing header. IPv6 clients controlling a typical /6...

NPM: Better Auth: Rate limiter keys IPv6 addresses individually and is bypassable via prefix rotation

NPM: Better Auth: Rate limiter keys IPv6 addresses individually and is bypassable via prefix rotation vulnerability discovered by ? in WordPress Npm better-auth versions 1.4.17...

GHSA-P6V2-XCPG-H6XW Better Auth: Rate limiter keys IPv6 addresses individually and is bypassable via prefix rotation

Am I affected? Users are affected if all of the following are true: - Their app uses better-auth at a version 1.4.17, or at a v1.5 prerelease tagged = 1.5.0-beta.8. - The apps authentication endpoints serve clients reachable over IPv6. Most managed hosts including Cloudflare, Vercel, Fly.io, AWS...