CVE-2021-39138

Workarounds

Don't use the createdWith Session field to make decisions if you allow anonymous login.

References

n/a

Developers that use the REST API to signup users and also allow users to login anonymously. When an anonymous user is first signed up using REST, the server creates session incorrectly, particularly the authProvider field in _Session class under createdWith shows the user logged in creating a password. If a developer later depends on the createdWith field to provide a different level of access between a password user and anonymous user, the server incorrectly classified the session type as being created with a password.

The server currently doesn't use createdWith to make decisions on how things work internally, so if a developer isn't using createdWith directly, there's nothing to worry about. The vulnerability only affects users who depend on createdWith by using it directly.

The application does not adequately verify the identity of a user, device, or process before granting access. Typical impact: unauthorized access to functions or data reserved for authenticated parties.

CVE-2021-39138 has a CVSS score of 4.8 (Medium). 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 (4.5.2); upgrading removes the vulnerable code path.

Kodem intelligence

Upgrade to version 4.5.1.

1. What is CVE-2021-39138? CVE-2021-39138 is a medium-severity improper authentication vulnerability in parse-server (npm), affecting versions < 4.5.2. It is fixed in 4.5.2. The application does not adequately verify the identity of a user, device, or process before granting access.
2. How severe is CVE-2021-39138? CVE-2021-39138 has a CVSS score of 4.8 (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.
3. Which versions of parse-server are affected by CVE-2021-39138? parse-server (npm) versions < 4.5.2 is affected.
4. Is there a fix for CVE-2021-39138? Yes. CVE-2021-39138 is fixed in 4.5.2. Upgrade to this version or later.
5. Is CVE-2021-39138 exploitable, and should I be worried? Whether CVE-2021-39138 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-2021-39138 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-2021-39138? Upgrade parse-server to 4.5.2 or later.

Other vulnerabilities in parse-server