CVE-2019-16254

Name	CVE-2019-16254
Description	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.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
References	DLA-2007-1, DLA-2027-1, DSA-4586-1, DSA-4587-1
NVD severity	medium

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
jruby (PTS)	jessie	1.5.6-9	vulnerable
	jessie (security)	1.5.6-9+deb8u2	fixed
	stretch (security), stretch	1.7.26-1+deb9u1	vulnerable
	bullseye, sid, buster	9.1.17.0-3	vulnerable
ruby2.1 (PTS)	jessie	2.1.5-2+deb8u3	vulnerable
	jessie (security)	2.1.5-2+deb8u8	fixed
ruby2.3 (PTS)	stretch	2.3.3-1+deb9u6	vulnerable
	stretch (security)	2.3.3-1+deb9u7	fixed
ruby2.5 (PTS)	buster	2.5.5-3	vulnerable
	buster (security)	2.5.5-3+deb10u1	fixed
	bullseye, sid	2.5.7-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Origin
jruby	source	(unstable)	(unfixed)
jruby	source	jessie	1.5.6-9+deb8u2	DLA-2027-1
ruby2.1	source	(unstable)	(unfixed)
ruby2.1	source	jessie	2.1.5-2+deb8u8	DLA-2007-1
ruby2.3	source	(unstable)	(unfixed)
ruby2.3	source	stretch	2.3.3-1+deb9u7	DSA-4587-1
ruby2.5	source	(unstable)	2.5.7-1
ruby2.5	source	buster	2.5.5-3+deb10u1	DSA-4586-1

Notes

https://github.com/ruby/ruby/commit/3ce238b5f9795581eb84114dcfbdf4aa086bfecc
https://hackerone.com/reports/331984
https://www.ruby-lang.org/en/news/2019/10/01/http-response-splitting-in-webrick-cve-2019-16254/