Summary
Reflected XSS when using flashMessages or languageDictionary
Overview
Versions before and including 11.30.0 are vulnerable to reflected XSS. An attacker can execute arbitrary code when the library's
flashMessagefeature is utilized and user input or data from URL parameters is incorporated into theflashMessage.languageDictionaryfeature is utilized and user input or data from URL parameters is incorporated into thelanguageDictionary.
Am I affected?
You are affected by this vulnerability if you are using auth0-lock version 11.30.0 or lower and all of the following conditions apply:
- You are utilizing
flashMessagefeature. - User input or data from URL parameters is incorporated into the
flashMessage.
An example of a vulnerable snippet where query parameters are used to populate the text property of a flashMessage.
var params = new URLSearchParams(location.search);
var errorMessage = params.get('error__message');
var showParams = {};
if (!!errorMessage === true) {
showParams.flashMessage = {
type: 'error',
text: 'We were unable to log you in. ' + errorMessage,
};
}
lock.show(showParams);
OR
- You are utilizing
languageDictionaryfeature. - User input or data from URL parameters is used in
languageDictionaryproperties.
An example of a vulnerable snippet where query parameters are used to populate the socialLoginInstructions property of a languageDictionary.
var params = new URLSearchParams(location.search);
var instruction = params.get('instruction');
var options = {
languageDictionary: {
emailInputPlaceholder: "[email protected]",
title: "title",
socialLoginInstructions: instruction
},
};
var lock = new Auth0LockPasswordless(
CLIENT_ID,
DOMAIN,
options
);
lock.show()
How to fix that?
Upgrade to version 11.30.1.
Will this update impact my users?
The fix uses DOMPurify to sanitise the flashMessage and languageDictionary inputs. If you are including inline JavaScript in these fields, like script tags or onclick attributes, these will be removed.
Impact
Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.
CVE-2021-32641 has a CVSS score of 8.1 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (11.30.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2021-32641? CVE-2021-32641 is a high-severity cross-site scripting (XSS) vulnerability in auth0-lock (npm), affecting versions < 11.30.1. It is fixed in 11.30.1. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- How severe is CVE-2021-32641? CVE-2021-32641 has a CVSS score of 8.1 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of auth0-lock are affected by CVE-2021-32641? auth0-lock (npm) versions < 11.30.1 is affected.
- Is there a fix for CVE-2021-32641? Yes. CVE-2021-32641 is fixed in 11.30.1. Upgrade to this version or later.
- Is CVE-2021-32641 exploitable, and should I be worried? Whether CVE-2021-32641 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2021-32641 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2021-32641? Upgrade
auth0-lockto 11.30.1 or later.