CVE-2025-71404 better-auth before 1.1.16 Reflected XSS via error parameter
Reflected XSS in better-auth allows attackers to execute arbitrary JavaScript in user browsers via a crafted error parameter URL.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2025-71404?
CVE-2025-71404 is a medium-severity cross-site scripting vulnerability in better-auth, published on 1 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
better-auth versions after v0.0.2 and before 1.1.16 contain a reflected cross-site scripting (XSS) vulnerability on the /api/auth/error page, where the value of the 'error' URL parameter is reflected as HTML without proper neutralization. An attacker who coerces a user into visiting a specially-crafted URL can execute arbitrary JavaScript in the context of the user's browser. The issue is fixed in version 1.1.16.
Weakness: CWE-79
Which versions are affected by CVE-2025-71404?
2 open source packages ship an affected version, including better-auth.
| Package | Affected | Fixed in |
|---|---|---|
better-auth npm | From 0.0.2 | 1.1.16 |
better-auth npm | From 0.0.2 | 1.1.16 |
How do I fix CVE-2025-71404?
Upgrade better-auth to 1.1.16 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2025-71404 being exploited?
There is no known exploitation of CVE-2025-71404 in the wild and no public exploit code.
Sources
Also known as GHSA-9x4v-xfq5-m8x5, GHSA-ch2q-47vm-cxgf.