CVE-2020-5247

HIGH EPSS 82.6%
Published Feb 28, 20206y ago · Modified Jun 17, 20262w ago
7.5 CVSS 3.1
High
Find Similar
Published Feb 28, 2020 6y ago
Last Modified Jun 17, 2026 2w ago

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 Details

Base Score
7.5
Exploitability
3.9
Impact
3.6
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality None
Integrity High
Availability None

Threat Intelligence

EPSS Exploit Probability
82.6% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 2

CWE-113
CWE-74

Affected Products 11

VendorProductVersionRange
pumapuma* ≤3.12.3
pumapuma*≥4.0.0  –  ≤4.3.2
ruby-langruby* ≤2.3.0
ruby-langruby*≥2.4.0  –  ≤2.4.7
ruby-langruby*≥2.5.0  –  ≤2.5.6
ruby-langruby*≥2.6.0  –  ≤2.6.4
ruby-langruby2.7.0any
debiandebian_linux9.0any
fedoraprojectfedora30any
fedoraprojectfedora31any
fedoraprojectfedora32any

References 7

  • github.com https://github.com/puma/puma/security/advisories/GHSA-84j7-475p-hp8v
    MitigationThird Party Advisory
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2022/05/msg00034.html
    Mailing ListThird Party Advisory
  • lists.fedoraproject.org https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BMJ3CGZ3DLBJ5WUUKMI5ZFXFJQMXJZIK/
  • lists.fedoraproject.org https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DIHVO3CQMU7BZC7FCTSRJ33YDNS3GFPK/
  • lists.fedoraproject.org https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NJ3LL5F5QADB6LM46GXZETREAKZMQNRD/
  • owasp.org https://owasp.org/www-community/attacks/HTTP_Response_Splitting
    Third Party Advisory
  • ruby-lang.org https://www.ruby-lang.org/en/news/2019/10/01/http-response-splitting-in-webrick-cve-2019-16254
    Vendor Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.