puma puma CVE-2020-5247 vulnerability in Puma and Other Products
Published on February 28, 2020

HTTP Response Splitting in Puma

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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.

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Vulnerability Analysis

CVE-2020-5247 can be exploited with network access, requires user interaction and a small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to be low. considered to have a small impact on confidentiality and integrity and availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
LOW
User Interaction:
REQUIRED
Scope:
CHANGED
Confidentiality Impact:
LOW
Integrity Impact:
LOW
Availability Impact:
LOW

Weakness Type

What is a HTTP Response Splitting Vulnerability?

The software receives data from an upstream component, but does not neutralize or incorrectly neutralizes CR and LF characters before the data is included in outgoing HTTP headers.

CVE-2020-5247 has been classified to as a HTTP Response Splitting vulnerability or weakness.


Products Associated with CVE-2020-5247

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2020-5247 are published in these products:

Puma
 
Ruby Programming Language Ruby Language
 
Debian Linux
 
Fedora Project Fedora
 

Affected Versions

Puma:

Vulnerable Packages

The following package name and versions may be associated with CVE-2020-5247

Package Manager Vulnerable Package Versions Fixed In
rubygems puma < 3.12.3 3.12.4
rubygems puma >= 4.0.0, < 4.3.2 4.3.3
rubygems puma < 3.12.4 3.12.4
rubygems puma >= 4.0.0, < 4.3.3 4.3.3

Exploit Probability

EPSS
2.09%
Percentile
83.78%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.