#VU79767 Inconsistent interpretation of HTTP requests in HAProxy - CVE-2023-40225

Vulnerability identifier: #VU79767

Vulnerability risk: Medium

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2023-40225

CWE-ID: CWE-444

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 perform HTTP request smuggling attacks.

The vulnerability exists due to improper validation of HTTP requests. A remote attacker can send a specially crafted HTTP request with empty Content-Length headers 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

HAProxy: 2.0.0 - 2.0.33, 2.1.0 - 2.1.12, 2.2.0 - 2.2.31, 2.3.0 - 2.3.21, 2.4.0 - 2.4.24, 2.5.0 - 2.5.14, 2.6.0 - 2.6.14, 2.7.0 - 2.7.9, 2.8.0 - 2.8.1

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External links
https://www.haproxy.org/download/2.8/src/CHANGELOG
https://www.haproxy.org/download/2.6/src/CHANGELOG
https://cwe.mitre.org/data/definitions/436.html
https://github.com/haproxy/haproxy/issues/2237
https://www.haproxy.org/download/2.7/src/CHANGELOG
https://github.com/haproxy/haproxy/commit/6492f1f29d738457ea9f382aca54537f35f9d856

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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.