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Package details: pkg:gem/puma@4.3.2
purl pkg:gem/puma@4.3.2
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Next non-vulnerable version 5.6.9
Latest non-vulnerable version 6.4.3
Risk 3.1
Vulnerabilities affecting this package (2)
Vulnerability Summary Fixed by
VCID-ap87-c4dc-zfcy
Aliases:
CVE-2020-5249
GHSA-33vf-4xgg-9r58
HTTP Response Splitting (Early Hints) in Puma ### Impact If an application using Puma allows untrusted input in an early-hints header, an attacker can use a carriage return character to end the header and inject malicious content, such as additional headers or an entirely new response body. This vulnerability is known as [HTTP Response Splitting](https://owasp.org/www-community/attacks/HTTP_Response_Splitting). While not an attack in itself, response splitting is a vector for several other attacks, such as cross-site scripting (XSS). This is related to [CVE-2020-5247](https://github.com/puma/puma/security/advisories/GHSA-84j7-475p-hp8v), which fixed this vulnerability but only for regular responses. ### Patches This has been fixed in 4.3.3 and 3.12.4. ### Workarounds Users can not allow untrusted/user input in the Early Hints response header. ### For more information If you have any questions or comments about this advisory: * Open an issue in [puma](https://github.com/puma/puma) * Email us a project maintainer. [Email addresses are listed in our Code of Conduct](https://github.com/puma/puma/blob/master/CODE_OF_CONDUCT.md#enforcement).
4.3.3
Affected by 9 other vulnerabilities.
VCID-pr2m-wx1b-hqbz
Aliases:
CVE-2020-5247
GHSA-84j7-475p-hp8v
HTTP Response Splitting in Puma In Puma (RubyGem) before 4.3.2 and 3.12.3, if an application using Puma allows untrusted input in a response header, an attacker can use newline characters (i.e. `CR`, `LF` or`/r`, `/n`) to end the header and inject malicious content, such as additional headers or an entirely new response body. This vulnerability is known as HTTP Response Splitting. While not an attack in itself, response splitting is a vector for several other attacks, such as cross-site scripting (XSS). This is related to CVE-2019-16254, which fixed this vulnerability for the WEBrick Ruby web server. This has been fixed in versions 4.3.2 and 3.12.3 by checking all headers for line endings and rejecting headers with those characters.
4.3.3
Affected by 9 other vulnerabilities.
Vulnerabilities fixed by this package (0)
Vulnerability Summary Aliases
This package is not known to fix vulnerabilities.

Date Actor Action Vulnerability Source VulnerableCode Version
2026-04-02T12:36:28.690017+00:00 GitLab Importer Affected by VCID-ap87-c4dc-zfcy https://gitlab.com/gitlab-org/advisories-community/-/blob/main/gem/puma/CVE-2020-5249.yml 38.0.0
2026-04-02T12:36:28.301418+00:00 GitLab Importer Affected by VCID-pr2m-wx1b-hqbz https://gitlab.com/gitlab-org/advisories-community/-/blob/main/gem/puma/CVE-2020-5247.yml 38.0.0