#VU55971 Input validation error in HAProxy


Published: 2021-08-18

Vulnerability identifier: #VU55971

Vulnerability risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-39242

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
HAProxy
Server applications / IDS/IPS systems, Firewalls and proxy servers

Vendor: HAProxy

Description

The vulnerability allows a remote attacker to bypass implemented security restrictions.

The vulnerability exists due to insufficient validation of user-supplied input when processing HTTP headers. A remote attacker can send a specially crafted Host header to the application and bypass implemented security restrictions.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

HAProxy: 2.2.0 - 2.2.15, 2.3.0 - 2.3.12, 2.4.0 - 2.4.2


External links
http://www.mail-archive.com/haproxy@formilux.org/msg41041.html
http://git.haproxy.org/?p=haproxy.git;a=commit;h=b5d2b9e154d78e4075db163826c5e0f6d31b2ab1


Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

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


Latest bulletins with this vulnerability