GHSA-w2pf-g6r8-pg22 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in auth0-lock. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-w2pf-g6r8-pg22 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
auth0-lock vulnerable to XSS via unsanitized placeholder property
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
auth0-locknpmDescription
Overview
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. a query parameter) could allow cross-site scripting (XSS) on their signup pages.
Am I affected?
You are affected by this vulnerability if all of the following conditions apply:
- You are using Auth0 Lock version 11.20.4 or earlier.
- You pass
additionalSignUpFieldsas options when initializing Lock which includes a field of typecheckboxwhoseplaceholdervalue is obtained from an untrusted source.
An example of a vulnerable snippet is the following where the placeholder value is partially user-controlled by the name query parameter:
<script>
var params = new URLSearchParams(window.location.search);
var options = {
auth: {
redirectUrl: 'http://localhost:12345/callback',
responseType: 'code',
params: {
scope: 'openid email',
},
},
additionalSignUpFields: [{
name: 'agree',
type: 'checkbox',
placeholder: "I agree to Terms and Conditions for " + params.get('name'),
}],
};
var lock = new Auth0Lock('<CLIENT_ID>', '<TENANT_NAME>.auth0.com', options);
lock.show({
allowShowPassword: true,
initialScreen: 'signUp',
});
</script>
How to fix that?
Developers using Auth0’s signin solution Lock need to upgrade to version 11.21.0 or later. Version 11.21.0 introduces two changes:
- The existing
placeholderproperty is now treated as plain text to mitigate the problem. - A new
placeholderHTMLproperty is introduced that indicates the level of control it provides and that it should be only supplied from trusted sources.
Will this update impact my users?
This fix patches the Auth0 Lock widget and may require changes in application code, but it will not impact your users, their current state, or any existing sessions.
Developers using the placeholder property with HTML content from a trusted source should start using the placeholderHTML property to continue providing the same user experience.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | auth0-lock | all versions | 11.21.0 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for auth0-lock. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update auth0-lock to 11.21.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-w2pf-g6r8-pg22 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-w2pf-g6r8-pg22 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-w2pf-g6r8-pg22. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-w2pf-g6r8-pg22 in your dependencies?
O3 detects GHSA-w2pf-g6r8-pg22 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.