This security advisory describes one medium risk vulnerability.
The vulnerability allows a remote attacker to perform HTTP request smuggling attack.
The vulnerability exists due to incorrect processing of messages with a missing transfer-encoding header, when HAProxy is configured in legacy mode. The server does not reject "chunked" value that combined with the "http-reuse always" setting can lead to HTTP request smuggling attack.
Install updates from vendor's website.Vulnerable software versions
HAProxy: 2.0.0, 2.0.1, 2.0.2, 2.0.3, 2.0.4, 2.0.5CPE
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.