What is CVE-2025-71403?

CVE-2025-71403 is a high-severity vulnerability in Better-auth, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 7.1/10. Published 2026-08-01.

How severe is CVE-2025-71403?

High severity. CVSS v3 base score is 7.1 out of 10.

Open Redirect in Better-auth

CVE-2025-71403

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…

Vulnerability class: Open Redirect

CVSS v3 metric

CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N.

Affected products

Better-auth — versions 0, 1.1.20

Weakness classification (CWE)

CWE-601 — URL Redirection to Untrusted Site (Open Redirect)

References

disclosure@vulncheck.com (vendor-advisory)
disclosure@vulncheck.com (third-party-advisory)

Frequently asked questions

What is CVE-2025-71403?: CVE-2025-71403 is a high-severity vulnerability in Better-auth, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 7.1/10. Published 2026-08-01.
How severe is CVE-2025-71403?: High severity. CVSS v3 base score is 7.1 out of 10.