Summary
User passwords are stored in clear text in the Django session
Workarounds
Switching Django's session storage to use signed cookies instead of the database or cache lessens the impact of this issue, but should not be done without a thorough understanding of the security tradeoffs of using signed cookies rather than a server-side session storage. There is no way to fully mitigate the issue without upgrading.
References
For an explanation of why storing cleartext password is a substantial vulnerability: Hashing Passwords: One-Way Road to Security.
For documentation on configuring the Django session storage engine: Django session documentation.
For more information
If you have any questions or comments about this advisory:
- Open an issue in the repo
Impact
django-two-factor-auth versions 1.11 and before store the user's password in clear text in the user session (base64-encoded). The password is stored in the session when the user submits their username and password, and is removed once they complete authentication by entering a two-factor authentication code. This means that the password is stored in clear text in the session for an arbitrary amount of time, and potentially forever if the user begins the login process by entering their username and password, and then leaves before entering their two-factor authentication code.
The severity of this issue depends on which type of session storage you have configured: in the worst case, if you're using Django's default database session storage, then users' password are stored in clear text in your database. In the best case, if you're using Django's signed cookie session, then users' passwords are only stored in clear text within their browser's cookie store. In the common case of using Django's cache session store, the users' password are stored in clear text in whatever cache storage you have configured (typically Memcached or Redis).
CVE-2020-15105 has a CVSS score of 5.4 (Medium). The vector is network-reachable, low 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 (1.12); 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.
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Upgrade to version 1.12 to resolve this issue.
After upgrading, users should be sure to delete any clear text passwords that have been stored. For example, if you're using the database session backend, you'll likely want to delete any session record from the database and purge that data from any database backups or replicas.
In addition, affected organizations who have suffered a database breach while using an affected version should inform their users that their clear text passwords have been compromised. All organizations should encourage users whose passwords were insecurely stored to change these passwords on any sites where they were used.
Frequently Asked Questions
- What is CVE-2020-15105? CVE-2020-15105 is a medium-severity security vulnerability in django-two-factor-auth (pip), affecting versions < 1.12. It is fixed in 1.12.
- How severe is CVE-2020-15105? CVE-2020-15105 has a CVSS score of 5.4 (Medium). 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 django-two-factor-auth are affected by CVE-2020-15105? django-two-factor-auth (pip) versions < 1.12 is affected.
- Is there a fix for CVE-2020-15105? Yes. CVE-2020-15105 is fixed in 1.12. Upgrade to this version or later.
- Is CVE-2020-15105 exploitable, and should I be worried? Whether CVE-2020-15105 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-2020-15105 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-2020-15105? Upgrade
django-two-factor-authto 1.12 or later.