CVE-2021-21416
LOWCVE-2021-21416 is a low-severity (CVSS 2.6) CWE-209 vulnerability in django-registration. O3 Security confirms whether CVE-2021-21416 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Potential sensitive information disclosed in error reports
Real-World Exposure
django-registrationReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
django-registration is a user registration package for Django. 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: 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 and 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).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | django-registration | all versions | 3.1.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for django-registration. 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 django-registration to 3.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21416 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 CVE-2021-21416 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 CVE-2021-21416. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2021-21416 in your dependencies?
O3 detects CVE-2021-21416 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.