CVE-2021-21416

Potential sensitive information disclosed in error reports

from django.utils.decorators import method_decorator
from django.views.decorators.debug import sensitive_post_parameters

from django_registration.views import RegistrationView

class MyRegistrationView(RegistrationView):
    """
    A RegistrationView subclass manually protected against sensitive information disclosure
    in error reports.

    """
    @method_decorator(sensitive_post_parameters())
    def dispatch(self, *args, **kwargs):
        return super().dispatch(*args, **kwargs)

The django-registration package provides tools for implementing user-account registration flows in the Django web framework. In django-registration prior to 3.1.2, the base user-account registration view did not properly apply filters to sensitive data, with the result that sensitive data could be included in error reports rather than removed automatically by Django.

Triggering this requires the following conditions:

• A site is using django-registration < 3.1.2
• The site has detailed error reports (such as Django's emailed error reports to site staff/developers) enabled
• A server-side error (HTTP 5xx) occurs during an attempt by a user to register an account

Under these conditions, recipients of the detailed error report will see all submitted data from the account-registration attempt, which may include the user's proposed credentials (such as a password).

CVE-2021-21416 has a CVSS score of 3.7 (Low). The vector is requires local access, high privileges required, and user interaction required. 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 (3.1.2); upgrading removes the vulnerable code path.

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As of version 3.1.2, django-registration properly applies Django's sensitive_post_parameters() decorator to the base user-registration view, which will cause all data from the HTTP request body to be filtered from detailed error reports in the event of a server-side crash during user account registration.

Note that as applied, this filters all HTTP request data from error reports. To selectively allow some fields but not others, see Django's own documentation (in references) and the notes below for how to apply sensitive_post_parameters() manually to a particular codebase's RegistrationView subclass(es).

1. What is CVE-2021-21416? CVE-2021-21416 is a low-severity security vulnerability in django-registration (pip), affecting versions < 3.1.2. It is fixed in 3.1.2.
2. How severe is CVE-2021-21416? CVE-2021-21416 has a CVSS score of 3.7 (Low). 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.
3. Which versions of django-registration are affected by CVE-2021-21416? django-registration (pip) versions < 3.1.2 is affected.
4. Is there a fix for CVE-2021-21416? Yes. CVE-2021-21416 is fixed in 3.1.2. Upgrade to this version or later.
5. Is CVE-2021-21416 exploitable, and should I be worried? Whether CVE-2021-21416 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
6. What actually determines whether CVE-2021-21416 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.
7. How do I fix CVE-2021-21416? Upgrade django-registration to 3.1.2 or later.