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CVE-2022-24790 Critical

HTTP Request Smuggling in puma

Puma is a simple, fast, multi-threaded, parallel HTTP 1.1 server for Ruby/Rack applications. 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 vulnerability has been fixed in 5.6.4 and 4.3.12. Users are advised to upgrade as soon as possible. Workaround: when deploying a proxy in front of Puma, turning on any and all functionality to make sure that the request matches the RFC7230 standard.

Exploit probability 2.1%
Published March 30, 2022
Required by Not available
Last source change August 12, 2026

02 / AFFECTED SOFTWARE

Affected packages

Unknown Unknown

117 explicit affected versions

RubyGems puma

146 explicit affected versions

03 / CONNECTIONS

Connected vulnerabilities

04 / EVIDENCE

Source records

Open Source Vulnerabilities CVE-2022-24790

Puma is a simple, fast, multi-threaded, parallel HTTP 1.1 server for Ruby/Rack applications. 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 vulnerability has been fixed in 5.6.4 and 4.3.12. Users are advised to upgrade as soon as possible. Workaround: when deploying a proxy in front of Puma, turning on any and all functionality to make sure that the request matches the RFC7230 standard.

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Open Source Vulnerabilities GHSA-h99w-9q5r-gjq9

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 "good" behavior re: this standard and upgrading Puma may not be necessary. Users are encouraged to validate for themselves. - Nginx (latest) - Apache (latest) - Haproxy 2.5+ - Caddy (latest) - Traefik (latest)

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05 / REFERENCES

Further evidence