Better Auth

Two researchers analyzed Better-Auth’s origin-check vulnerability, detailing open redirect risks and a patch that followed disclosures. The write-up traces how trustedOrigins validation could still be bypassed and notes a subsequent patch and vulnerability reporting by multiple researchers.
#Better-Auth #OpenRedirect #trustedOrigins #OpenRedirectVulnerability #PatchDeployment

Keypoints

Better-auth is an open-source TypeScript library that handles multiple authentication flows.
Origin-check middleware validates URLs against trustedOrigins to prevent redirects.
Initial bypasses exploited a logic condition combining startsWith(“/”) with URL pattern checks and lacked protection for certain URL forms.
Researchers demonstrated bypass scenarios including //attacker.com and wildcard patterns, prompting patches.
A patch tightened checks by excluding URLs starting with // and added safeguards against wildcard-based exploits.