8.0
High
puma

CVE-2022-23634

CVE-2022-23634 is a high-severity security vulnerability in puma (rubygems), affecting versions >= 5.0.0, < 5.6.2. It is fixed in 5.6.2, 4.3.11.

Key facts
CVSS score
8.0
High
Attack vector
Network
Issuing authority
GitHub Advisory Database
Affected package
puma
Fixed in
5.6.2, 4.3.11
Disclosed
2022

Summary

Impact Prior to puma version 5.6.2, puma may not always call close on the response body. Rails, prior to version 7.0.2.2, depended on the response body being closed in order for its CurrentAttributes implementation to work correctly. From Rails: Under certain circumstances response bodies will not be closed, for example a bug in a webserver[1] or a bug in a Rack middleware. In the event a response is not notified of a close, ActionDispatch::Executor will not know to reset thread local state for the next request. This can lead to data being leaked to subsequent requests, especially when interacting with ActiveSupport::CurrentAttributes. The combination of these two behaviors (Puma not closing the body + Rails' Executor implementation) causes information leakage. Patches This problem is fixed in Puma versions 5.6.2 and 4.3.11. This problem is fixed in Rails versions 7.02.2, 6.1.4.6, 6.0.4.6, and 5.2.6.2. See: https://github.com/advisories/GHSA-wh98-p28r-vrc9 for details about the rails vulnerability Upgrading to a patched Rails or Puma version fixes the vulnerability. Workarounds Upgrade to Rails versions 7.02.2, 6.1.4.6, 6.0.4.6, and 5.2.6.2. The Rails CVE includes a middleware that can be used instead. References Rails CVE: CVE-2022-23633 For more information If you have any questions or comments about this advisory: Open an issue in puma See our security policy

Impact

Severity and exposure

CVE-2022-23634 has a CVSS score of 8.0 (High). The vector is network-reachable, no 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 (5.6.2, 4.3.11). Upgrading removes the vulnerable code path.

Affected versions

rubygems

  • puma (>= 5.0.0, < 5.6.2)
  • puma (< 4.3.11)

Security releases

  • puma → 5.6.2 (rubygems)
  • puma → 4.3.11 (rubygems)
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 instead of chasing every advisory.

Kodem's runtime-powered SCA identifies whether CVE-2022-23634 is reachable in your applications. Explore open-source security for your team.

See if CVE-2022-23634 is reachable in your applications. Get a demo

Remediation advice

Upgrade the following packages to resolve this vulnerability:

  • Upgrade puma to 5.6.2 or later
  • Upgrade puma to 4.3.11 or later

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently asked questions about CVE-2022-23634

What is CVE-2022-23634?

CVE-2022-23634 is a high-severity security vulnerability in puma (rubygems), affecting versions >= 5.0.0, < 5.6.2. It is fixed in 5.6.2, 4.3.11.

How severe is CVE-2022-23634?

CVE-2022-23634 has a CVSS score of 8.0 (High). 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 puma are affected by CVE-2022-23634?

puma (rubygems) versions >= 5.0.0, < 5.6.2 is affected.

Is there a fix for CVE-2022-23634?

Yes. CVE-2022-23634 is fixed in 5.6.2, 4.3.11. Upgrade to this version or later.

Is CVE-2022-23634 exploitable, and should I be worried?

Whether CVE-2022-23634 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-2022-23634 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-2022-23634?
  • Upgrade puma to 5.6.2 or later
  • Upgrade puma to 4.3.11 or later

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