MEDIUM
Ruby through 2.4.7, 2.5.x through 2.5.6, and 2.6.x through 2.6.4 allows HTTP Response Splitting. If a program using WEBrick inserts untrusted input into the response header, an attacker can exploit it to insert a newline character to split a header, and inject malicious content to deceive clients. NOTE: this issue exists because of an incomplete fix for CVE-2017-17742, which addressed the CRLF vector, but did not address an isolated CR or an isolated LF.
http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00041.html
https://hackerone.com/reports/331984
https://lists.debian.org/debian-lts-announce/2019/11/msg00025.html
https://lists.debian.org/debian-lts-announce/2019/12/msg00009.html
https://lists.debian.org/debian-lts-announce/2020/08/msg00027.html
https://seclists.org/bugtraq/2019/Dec/31
https://seclists.org/bugtraq/2019/Dec/32
https://security.gentoo.org/glsa/202003-06
https://www.debian.org/security/2019/dsa-4586
https://www.debian.org/security/2019/dsa-4587
https://www.oracle.com/security-alerts/cpujan2020.html
https://www.ruby-lang.org/ja/news/2019/10/01/http-response-splitting-in-webrick-cve-2019-16254/
https://www.ruby-lang.org/ja/news/2019/10/01/ruby-2-4-8-released/
https://www.ruby-lang.org/ja/news/2019/10/01/ruby-2-5-7-released/
https://www.ruby-lang.org/ja/news/2019/10/01/ruby-2-6-5-released/
Source: MITRE
Published: 2019-11-26
Updated: 2020-08-16
Type: CWE-74
Base Score: 5
Vector: AV:N/AC:L/Au:N/C:N/I:P/A:N
Impact Score: 2.9
Exploitability Score: 10
Severity: MEDIUM
Base Score: 5.3
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Impact Score: 1.4
Exploitability Score: 3.9
Severity: MEDIUM