XSS in Auth0 Nextjs-Auth0

CVE-2021-32702

The Auth0 Next.js SDK is a library for implementing user authentication in Next.js applications. Versions before and including `1.4.1` are vulnerable to reflected XSS. An attacker can execute arbitrary code by providing an XSS payload in the `error` query parameter which is then processed by the callback handler as an error message. You are affected by this vulnerability if you are using `@auth0/nextjs-auth0` version `1.4.1` or lower **unless** you are using custom error handling that does not return the error message in an HTML response. Upgrade to version `1.4.1` to resolve. The fix adds basic HTML escaping to the error message and it should not impact your users.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.014 (69.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.0 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2021-32702?
CVE-2021-32702 is a high-severity vulnerability in Auth0 Nextjs-Auth0, classified under Cross-site Scripting. CVSS score: 8.0/10. Published 2021-06-25.
How severe is CVE-2021-32702?
High severity. CVSS v3 base score is 8.0 out of 10.