Puma vulnerable to HTTP Request Smuggling

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

9.1 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS

• CVE-2022-24790: 2.19% estimated exploitation activity in the next 30 days; percentile 82.47 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

When using Puma behind a proxy that does not properly validate that the incoming HTTP request matches the RFC7230 standard, Puma and the frontend proxy may disagree on where a request starts and ends. This would allow requests to be smuggled via the front-end proxy to Puma. The following vulnerabilities are addressed by this advisory: - Lenient parsing of Transfer-Encoding headers, when unsupported encodings should be rejected and the final encoding must be chunked. - Lenient parsing of malformed Content-Length headers and chunk sizes, when only digits and hex digits should be allowed. - Lenient parsing of duplicate Content-Length headers, when they should be rejected. - Lenient parsing of the ending of chunked segments, when they should end with \r\n. The vulnerability has been fixed in 5.6.4 and 4.3.12. When deploying a proxy in front of Puma, turning on any and all functionality to make sure that the request matches the RFC7230 standard. These proxy servers are known to have…

Published by the source

30 Mar 2022, 21:48 UTC

Last modified by the source

4 May 2023, 19:51 UTC

Source last checked

26 Oct 2026, 15:47 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-h99w-9q5r-gjq9

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# Patch Next advisory brief: CVE-2022-24790

Advisory: Puma vulnerable to HTTP Request Smuggling
IDs: CVE-2022-24790, GHSA-h99w-9q5r-gjq9
Record: https://patchnext.com/advisories/cve-2022-24790 (revision 1, source checked 26 Oct 2026, 15:47 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: puma 5.6.4, 4.3.12. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems puma: affected >= 5.0.0, < 5.6.4; < 4.3.12; fixed in 4.3.12, 5.6.4

## Suggested inspection (read-only)
- RubyGems puma: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on puma.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-h99w-9q5r-gjq9 (GitHub-reviewed advisory GHSA-h99w-9q5r-gjq9 lists affected ranges: RubyGems puma >=5.0.0 =0 <4.3.12)

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