CVE-2020-5247 Information

Description

In Puma (RubyGem) before 4.3.2 and before 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.

CVSS Vector

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

Reference

https://github.com/puma/puma/security/advisories/GHSA-84j7-475p-hp8v https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/BMJ3CGZ3DLBJ5WUUKMI5ZFXFJQMXJZIK/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DIHVO3CQMU7BZC7FCTSRJ33YDNS3GFPK/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NJ3LL5F5QADB6LM46GXZETREAKZMQNRD/ https://owasp.org/www-community/attacks/HTTP_Response_Splitting https://www.ruby-lang.org/en/news/2019/10/01/http-response-splitting-in-webrick-cve-2019-16254

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

HIGH

Base Score

NONE

Base Severity

7.5