GHSA-9x4v-xfq5-m8x5 – better-auth

Package

Manager: npm
Name: better-auth
Vulnerable Version: >=0.0.2 <1.1.16

Severity

Level: Critical

CVSS v3.1: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

EPSS: N/A pctlN/A

Details

Better Auth URL parameter HTML Injection (Reflected Cross-Site scripting) ### Summary The better-auth `/api/auth/error` page was vulnerable to HTML injection, resulting in a reflected cross-site scripting (XSS) vulnerability. ### Details The value of `error` URL parameter was reflected as HTML on the error page: https://github.com/better-auth/better-auth/blob/05ada0b79dbcac93cc04ceb79b23ca598d07830c/packages/better-auth/src/api/routes/error.ts#L81 ### PoC https://demo.better-auth.com/api/auth/error?error=%3Cscript%3Ealert(1)%3C/script%3E  ### Impact An attacker who exploited this vulnerability by coercing a user to visit a specially-crafted URL could execute arbitrary JavaScript in the context of the user's browser. Because better-auth is a dependency of web applications, the impact of such a vulnerability is unknowable; it depends on the functionality of the application/site using better-auth. I have calculated the CVSS score assuming the hypothetical victim is an administrator with elevated permissions and access.

Metadata

Created: 2025-02-05T21:49:39Z
Modified: 2025-02-05T21:49:39Z
Source: https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/02/GHSA-9x4v-xfq5-m8x5/GHSA-9x4v-xfq5-m8x5.json
CWE IDs: ["CWE-79"]
Alternative ID: N/A
Finding: F008
Auto approve: 1