RubySec

Providing security resources for the Ruby community

CVE-2020-5247 (puma): HTTP Response Splitting vulnerability in puma

ADVISORIES

GEM

puma

SEVERITY

CVSS v3: 6.5

PATCHED VERSIONS

  • ~> 3.12.4
  • >= 4.3.3

DESCRIPTION

If an application using Puma allows untrusted input in a response header, an attacker can use newline characters (i.e. CR, LF) 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).