CVE-2025-71404

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.

Score

CVSS 4.0 5.1 Medium

Status

Deferred - disclosure@vulncheck.com

Published

2026-08-01

Last modified

2026-10-06

Weaknesses

CWE-79

Affected products

• Better-auth/oauth-provider (Better-auth)

References

• https://github.com/better-auth/better-auth/security/advisories/GHSA-9x4v-xfq5-m8x5
• https://github.com/better-auth/better-auth/commit/05ada0b79dbcac93cc04ceb79b23ca598d07830c
• https://www.vulncheck.com/advisories/better-auth-before-reflected-xss-via-error-parameter