GHSA-hjpm-7mrm-26w8

Beter Auth has an Open Redirect via Scheme-Less Callback Parameter

Description

### Summary The application is vulnerable to an open redirect due to improper validation of the callbackURL parameter in the email verification endpoint and any other endpoint that accepts callback url. While the server blocks fully qualified URLs (e.g., https://evil.com), it incorrectly allows scheme-less URLs (e.g., //malicious-site.com). This results in the browser interpreting the URL as https://malicious-site.com, leading to unintended redirection. bypass for : https://github.com/better-auth/better-auth/security/advisories/GHSA-8jhw-6pjj-8723 ### Affected Versions All versions prior to 1.1.19 ### Details The application’s email verification endpoint (/auth/verify-email) accepts a callbackURL parameter intended to redirect users after successful email verification. While the server correctly blocks fully qualified external URLs (e.g., https://evil.com), it improperly allows scheme-less URLs (e.g., //malicious-site.com). This issue occurs because browsers interpret //malicious-site.com as https://malicious-site.com, leading to an open redirect vulnerability. An attacker can exploit this flaw by crafting a malicious verification link and tricking users into clicking it. Upon successful email verification, the user will be automatically redirected to the attacker's website, which can be used for phishing, malware distribution, or stealing sensitive authentication tokens. ### Impact Phishing & Credential Theft – Attackers can redirect users to a fake login page, tricking them into entering sensitive credentials, which can then be stolen. Session Hijacking & Token Theft – If used in OAuth flows, an attacker could redirect authentication tokens to their own domain, leading to account takeover.

Affected packages

References

• https://github.com/better-auth/better-auth/security/advisories/GHSA-8jhw-6pjj-8723 WEB
• https://github.com/better-auth/better-auth/security/advisories/GHSA-hjpm-7mrm-26w8 WEB
• https://nvd.nist.gov/vuln/detail/CVE-2025-27143 ADVISORY
• https://github.com/better-auth/better-auth/commit/24659aefc35a536b95ea4e5347e52c8803910153 WEB
• https://github.com/better-auth/better-auth/commit/b381cac7aafd6aa53ef78b6ab771ebfa24643c80 WEB
• https://github.com/better-auth/better-auth PACKAGE
• https://github.com/better-auth/better-auth/releases/tag/v1.1.21 WEB

Sources