HTTP request smuggling in Puma

1) Inconsistent interpretation of HTTP requests

EUVDB-ID: #VU63634

Risk: Medium

CVSSv3.1: 5.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-41136

CWE-ID: CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling')

Exploit availability: No

Description

The vulnerability allows a remote attacker to preform HTTP request smuggling attacks.

The vulnerability exists due to improper validation of HTTP requests. A remote attacker can send a specially crafted HTTP header values which contain the LF character to the server and smuggle arbitrary HTTP headers.

Successful exploitation of vulnerability may allow an attacker to poison HTTP cache and perform phishing attacks.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Puma: 4.0.0 - 5.5.0

External links

http://github.com/puma/puma/security/advisories/GHSA-48w2-rm65-62xx
http://github.com/puma/puma/commit/acdc3ae571dfae0e045cf09a295280127db65c7f
http://www.debian.org/security/2022/dsa-5146

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.