auth0-lock vulnerable to XSS via unsanitized placeholder property

Description

Auth0 Lock version 11.20.4 and earlier did not properly sanitize the generated HTML code. Customers using the additionalSignUpFields customization option to add a checkbox to the sign-up dialog that are passing a placeholder property obtained from an untrusted source (e.g.

Recommendation

Update the auth0-lock package to the latest compatible version. Followings are version details:

• Affected version(s): < 11.21.0
• Patched version(s): 11.21.0

References

• GHSA-w2pf-g6r8-pg22
• auth0.com
• CVE-2019-20174
• CWE-79
• CAPEC-310
• OWASP 2021-A3
• OWASP 2021-A6

Related Issues

• DOM-based XSS in auth0-lock - CVE-2020-15119
• Astro vulnerable to reflected XSS via the server islands feature - CVE-2025-64764
• sanitize-html is vulnerable to XSS through incomprehensive sanitization - CVE-2019-25225
• jsondiffpatch is vulnerable to Cross-site Scripting (XSS) via HtmlFormatter::nodeBegin - CVE-2025-9910

Tags:

npm

auth0-lock