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 open redirects to steal sensitive tokens for account takeover.

Vulnerability class: Open Redirect

EPSS: 0.002 (15.0th percentile) — read the EPSS interpretation.

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.