All vulnerabilities

Servers and applications

CVE-2020-5247

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…

Severity
High 7.5
Published
28 Feb 2020
Last changed
17 Jun 2026
Added to UpHeron
21 Oct 2026
Sources
NVD

Affected software

SoftwareAffected versions
RubyServers and applications · cpe:a:ruby-lang:ruby
  • Every version up to 2.3.0
  • From 2.4.0 up to 2.4.7
  • From 2.5.0 up to 2.5.6
  • From 2.6.0 up to 2.6.4
  • Version 2.7.0-preview1

References

  • NVD https://nvd.nist.gov/vuln/detail/CVE-2020-5247
  • CVE.org https://www.cve.org/CVERecord?id=CVE-2020-5247