What is CVE-2023-22477?

CVE-2023-22477 is a medium-severity security vulnerability in mercurius (npm), affecting versions >= 9.0.0, < 11.5.0. It is fixed in 11.5.0, 8.13.2.

How severe is CVE-2023-22477?

CVE-2023-22477 has a CVSS score of 5.3 (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 mercurius are affected by CVE-2023-22477?

mercurius (npm) versions >= 9.0.0, < 11.5.0 is affected.

Is there a fix for CVE-2023-22477?

Yes. CVE-2023-22477 is fixed in 11.5.0, 8.13.2. Upgrade to this version or later.

Is CVE-2023-22477 exploitable, and should I be worried?

Whether CVE-2023-22477 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-2023-22477 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-2023-22477?

Upgrade: mercurius to 11.5.0 or later, mercurius to 8.13.2 or later.

CVE-2023-22477 in mercurius | Intelligent Application Security

Q: How severe is CVE-2023-22477?

CVE-2023-22477 has a CVSS score of 5.3 (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.

Q: Which versions of mercurius are affected by CVE-2023-22477?

mercurius (npm) versions >= 9.0.0, < 11.5.0 is affected.

Q: Is there a fix for CVE-2023-22477?

Yes. CVE-2023-22477 is fixed in 11.5.0, 8.13.2. Upgrade to this version or later.

Q: Is CVE-2023-22477 exploitable, and should I be worried?

Whether CVE-2023-22477 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-2023-22477 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-2023-22477?

Upgrade: mercurius to 11.5.0 or later, mercurius to 8.13.2 or later.

Summary

Workarounds

Disable subscriptions.

References

Reported publicly as https://github.com/mercurius-js/mercurius/issues/939.
The same problem was solved in https://github.com/fastify/fastify-websocket/pull/228

Impact

Any users of Mercurius until version v11.5.0 are subjected to a denial of service attack by sending a malformed packet over WebSocket to /graphql.

CVE-2023-22477 has a CVSS score of 5.3 (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 (11.5.0, 8.13.2); upgrading removes the vulnerable code path.

Affected versions

mercurius (>= 9.0.0, < 11.5.0) mercurius (< 8.13.2)

Security releases

mercurius → 11.5.0 (npm) mercurius → 8.13.2 (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.

See it in your environment

Remediation advice

This was patched in https://github.com/mercurius-js/mercurius/pull/940.
The patch was released as v11.5.0 and v8.13.2.

Frequently Asked Questions

What is CVE-2023-22477? CVE-2023-22477 is a medium-severity security vulnerability in mercurius (npm), affecting versions >= 9.0.0, < 11.5.0. It is fixed in 11.5.0, 8.13.2.
How severe is CVE-2023-22477? CVE-2023-22477 has a CVSS score of 5.3 (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 mercurius are affected by CVE-2023-22477? mercurius (npm) versions >= 9.0.0, < 11.5.0 is affected.
Is there a fix for CVE-2023-22477? Yes. CVE-2023-22477 is fixed in 11.5.0, 8.13.2. Upgrade to this version or later.
Is CVE-2023-22477 exploitable, and should I be worried? Whether CVE-2023-22477 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-2023-22477 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-2023-22477?
- Upgrade mercurius to 11.5.0 or later
- Upgrade mercurius to 8.13.2 or later

Other vulnerabilities in mercurius

CVE-2026-30241 CVE-2023-22477 CVE-2021-43801