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Vulnerability · Published Feb 28, 2020 · Assigned by GitHub_M

CVE-2020-5247HTTP Response Splitting in Puma

Medium 6.5

In plain English

A medium-severity security flaw in Puma from puma. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 2.5% (higher than 85% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.5Medium
Exploit odds (30 days)2.5%top 14.9% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12puma3.12.4-1DEBIAN-CVE-2020-5247
Debian:13puma3.12.4-1DEBIAN-CVE-2020-5247
Debian:14puma3.12.4-1DEBIAN-CVE-2020-5247
RubyGemspuma3.12.4GHSA-84j7-475p-hp8v
RubyGemspuma4.3.3GHSA-84j7-475p-hp8v

Affected products (as reported)

VendorProductVersions
puma Puma < 3.12.3>= 4.0.0, < 4.3.2

Weakness: CWE-113 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L

References