CVE-2020-5247

NameCVE-2020-5247
DescriptionIn 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
NVD severitymedium
Debian Bugs952766

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
puma (PTS)stretch3.6.0-1vulnerable
stretch (security)3.6.0-1+deb9u1vulnerable
buster3.12.0-2+deb10u1vulnerable
bullseye, sid4.3.6-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
pumasource(unstable)3.12.4-1952766

Notes

[buster] - puma <no-dsa> (Minor issue)
[stretch] - puma <no-dsa> (intrusive to backport)
https://github.com/puma/puma/security/advisories/GHSA-84j7-475p-hp8v
https://github.com/puma/puma/commit/1b17e85a06183cd169b41ca719928c26d44a6e03 (3.12.3)
https://github.com/puma/puma/commit/694feafcd4fdcea786a0730701dad933f7547bea (4.3.2)

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