Is CVE-2025-71403 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2025-71403 being exploited in the wild.

How severe is CVE-2025-71403?

High severity, with a CVSS score of 7.1, published 1 August 2026.

Which products and versions are affected?

better-auth (npm) SEMVER:introduced=0,fixed=1.1.21.

Is there a fix for CVE-2025-71403?

Yes. better-auth (npm): upgrade to 1.1.21 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2025-71403 attacked?

It is attacked over the network.

Am I affected by CVE-2025-71403?

Check whether you run better-auth (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2025-71403: Better Auth trustedOrigins bypass leading to account takeover

CVE-2025-71403 · Severity: high · CVSS 7.1 · Published 2026-08-01

Better Auth is a JavaScript authentication library used to manage user login and password reset flows. A flaw in the origin validation logic allows attackers to bypass security checks and redirect users to malicious sites, potentially stealing sensitive tokens used for password reset—enabling one-click account takeover if victims click a crafted link.

Technologies: better-auth (npm). Vendors: npm.

Quick answers

Is CVE-2025-71403 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2025-71403 being exploited in the wild.
How severe is CVE-2025-71403?: High severity, with a CVSS score of 7.1, published 1 August 2026.
Which products and versions are affected?: better-auth (npm) SEMVER:introduced=0,fixed=1.1.21.
Is there a fix for CVE-2025-71403?: Yes. better-auth (npm): upgrade to 1.1.21 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2025-71403 attacked?: It is attacked over the network.
Am I affected by CVE-2025-71403?: Check whether you run better-auth (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

better-auth (npm): upgrade to 1.1.21 or later
```
npm install better-auth@1.1.21
```

Technical details

The vulnerability is an open redirect (CWE-601) caused by improper validation of the trustedOrigins configuration in Better Auth. The origin-check middleware fails to properly validate both absolute URLs and wildcard domain patterns, allowing an attacker to craft a malicious callbackURL that passes origin checks yet redirects to an attacker-controlled destination. The flaw requires user interaction (victim must click the crafted link) and is network-accessible with no authentication required. Exploitation can lead to token theft and account takeover. The issue is patched in version 1.1.21 and affects all versions up to 1.1.20.

Affected products

Better Auth better-auth <=1.1.20

Identifiers

CVE-2025-71403
GHSA-vp58-j275-797x

Timeline

2025-02-24: disclosed
2025-02-24: patched: patched in version 1.1.21

References

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