CVE-2021-32641
Reflected XSS when using flashMessages
auth0-lock is Auth0's signin solution. Versions of nauth0-lock before and including 11.30.0 are vulnerable to reflected XSS. An attacker can execute arbitrary code when the library's flashMessage feature is utilized and user input or data from URL parameters is incorporated into the flashMessage or the library's languageDictionary feature is utilized and user input or data from URL parameters is incorporated into the languageDictionary. The vulnerability is patched in version 11.30.1.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
8.1
Reflected XSS when using flashMessages
auth0-lock is Auth0's signin solution. Versions of nauth0-lock before and including 11.30.0 are vulnerable to reflected XSS. An attacker can execute arbitrary code when the library's flashMessage feature is utilized and user input or data from URL parameters is incorporated into the flashMessage or the library's languageDictionary feature is utilized and user input or data from URL parameters is incorporated into the languageDictionary. The vulnerability is patched in version 11.30.1.
- Record
CVE-2021-32641- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2021-1348
8.1
auth0-lock is Auth0's signin solution. Versions of nauth0-lock before and including 11.30.0 are vulnerable to reflected XSS. An attacker can execute arbitrary code when the library's flashMessage feature is utilized and user input or data from URL parameters is incorporated into the flashMessage or the library's languageDictionary feature is utilized and user input or data from URL parameters is incorporated into the languageDictionary. The vulnerability is patched in version 11.30.1.
- Record
EUVD-2021-1348- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-jr3j-whm4-9wwm
8.1
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.
- Record
GHSA-jr3j-whm4-9wwm- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-79
- Updated
- 2026-11-02
NVD
8.1
auth0-lock is Auth0's signin solution. Versions of nauth0-lock before and including 11.30.0 are vulnerable to reflected XSS. An attacker can execute arbitrary code when the library's flashMessage feature is utilized and user input or data from URL parameters is incorporated into the flashMessage or the library's languageDictionary feature is utilized and user input or data from URL parameters is incorporated into the languageDictionary. The vulnerability is patched in version 11.30.1.
- Record
CVE-2021-32641- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:P/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
6.1
auth0-lock is Auth0's signin solution. Versions of nauth0-lock before and including 11.30.0 are vulnerable to reflected XSS. An attacker can execute arbitrary code when the library's flashMessage feature is utilized and user input or data from URL parameters is incorporated into the flashMessage or the library's languageDictionary feature is utilized and user input or data from URL parameters is incorporated into the languageDictionary. The vulnerability is patched in version 11.30.1.
- Record
CVE-2021-32641- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
OSVGHSA-jr3j-whm4-9wwm
8.1
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.
- Record
GHSA-jr3j-whm4-9wwm- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-79
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
auth0-locknpm |
before 11.30.1 | 11.30.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-32641 is a high vulnerability (CVSS 8.1) in Auth0 Lock, published June 4, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.54%, the 75th percentile. Fixed in auth0-lock 11.30.1.