Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2020-5247

Severity CVSS v4.0:
Pending analysis
Type:
CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Response Splitting')
Publication date:
28/02/2020
Last modified:
07/11/2023

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.

Impact

Vector 3.x
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N CVSS v3.1 Severity and Metrics:

Base Score: 7.50 HIGH
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): High
Availability (A): None

Base Score 3.x
7.50
Severity 3.x
HIGH
Vector 2.0
AV:N/AC:L/Au:N/C:N/I:P/A:N CVSS v2.0 Severity and Metrics:

Base Score: 5.00 MEDIUM
Vector: AV:N/AC:L/Au:N/C:N/I:P/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Authentication (Au): None
Confidentiality (C): None
Integrity (I): Physical
Availability (A): None

Base Score 2.0
5.00
Severity 2.0
MEDIUM

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:puma:puma:*:*:*:*:*:ruby:*:* 3.12.3 (including)
cpe:2.3:a:puma:puma:*:*:*:*:*:ruby:*:* 4.0.0 (including) 4.3.2 (including)
cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:* 2.3.0 (including)
cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:* 2.4.0 (including) 2.4.7 (including)
cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:* 2.5.0 (including) 2.5.6 (including)
cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:* 2.6.0 (including) 2.6.4 (including)
cpe:2.3:a:ruby-lang:ruby:2.7.0:preview1:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools