What is CVE-2022-23631?

CVE-2022-23631 is a critical-severity code injection vulnerability in superjson (npm), affecting versions < 1.8.1. It is fixed in 1.8.1, 0.45.3. Untrusted input is evaluated as executable code within the application's runtime environment.

How severe is CVE-2022-23631?

CVE-2022-23631 has a CVSS score of 9.0 (Critical). 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 packages are affected by CVE-2022-23631?

superjson (npm) versions < 1.8.1; blitz (npm) versions < 0.45.3.

Is there a fix for CVE-2022-23631?

Yes. CVE-2022-23631 is fixed in 1.8.1, 0.45.3. Upgrade to this version or later.

Is CVE-2022-23631 exploitable, and should I be worried?

Whether CVE-2022-23631 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.

What actually determines whether CVE-2022-23631 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-2022-23631?

Upgrade: superjson to 1.8.1 or later, blitz to 0.45.3 or later.

CVE-2022-23631 in superjson

Q: How severe is CVE-2022-23631?

CVE-2022-23631 has a CVSS score of 9.0 (Critical). 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.

Q: Which packages are affected by CVE-2022-23631?

superjson (npm) versions < 1.8.1; blitz (npm) versions < 0.45.3.

Q: Is there a fix for CVE-2022-23631?

Yes. CVE-2022-23631 is fixed in 1.8.1, 0.45.3. Upgrade to this version or later.

Q: Is CVE-2022-23631 exploitable, and should I be worried?

Whether CVE-2022-23631 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.

Q: What actually determines whether CVE-2022-23631 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.

Q: How do I fix CVE-2022-23631?

Upgrade: superjson to 1.8.1 or later, blitz to 0.45.3 or later.

Summary

Prototype Pollution leading to Remote Code Execution in superjson

Workarounds

None

For more information

If you have any questions or comments about this advisory:

Open an issue in https://github.com/blitz-js/superjson
Email us at [email protected]

References

https://www.sonarsource.com/blog/blitzjs-prototype-pollution/

Impact

This is critical vulnerability, as it allows to run arbitrary code on any server using superjson input, including a Blitz.js server, without prior authentication or knowledge. Attackers gain full control over the server so they could steal and manipulate data or attack further systems. The only requirement is that the server implements at least one endpoint which uses superjson during request processing. In the case of Blitz.js, it would be at least one RPC call.

Untrusted input is evaluated as executable code within the application's runtime environment. Typical impact: arbitrary code execution within the application's privilege context.

CVE-2022-23631 has a CVSS score of 9.0 (Critical). 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 (1.8.1, 0.45.3); upgrading removes the vulnerable code path.

Affected versions

superjson (< 1.8.1) blitz (< 0.45.3)

Security releases

superjson → 1.8.1 (npm) blitz → 0.45.3 (npm)

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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Remediation advice

This has been patched in superjson 1.8.1 and Blitz.js 0.45.3.

If you are unable to upgrade to Blitz.js 0.45.3 in a timely manner, you can instead upgrade only superjson to version 1.8.1 using yarn resolutions are similar. Blitz versions < 0.45.3 are only affected because they used superjson versions < 1.8.1.

Frequently Asked Questions

What is CVE-2022-23631? CVE-2022-23631 is a critical-severity code injection vulnerability in superjson (npm), affecting versions < 1.8.1. It is fixed in 1.8.1, 0.45.3. Untrusted input is evaluated as executable code within the application's runtime environment.
How severe is CVE-2022-23631? CVE-2022-23631 has a CVSS score of 9.0 (Critical). 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 packages are affected by CVE-2022-23631?
- superjson (npm) (versions < 1.8.1)
- blitz (npm) (versions < 0.45.3)
Is there a fix for CVE-2022-23631? Yes. CVE-2022-23631 is fixed in 1.8.1, 0.45.3. Upgrade to this version or later.
Is CVE-2022-23631 exploitable, and should I be worried? Whether CVE-2022-23631 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-2022-23631 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-2022-23631?
- Upgrade superjson to 1.8.1 or later
- Upgrade blitz to 0.45.3 or later