#VU83902 Input validation error in HAProxy - CVE-2023-45539

Vulnerability identifier: #VU83902

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2023-45539

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 gain access to sensitive information.

The vulnerability exists due to insufficient validation of user-supplied input when processing the "#" character in the URI. A remote attacker can pass specially crafted URI to the application and view otherwise restricted file or potentially manipulate data.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

HAProxy: 2.8.0 - 2.8.1

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External links
https://lists.w3.org/Archives/Public/ietf-http-wg/2023JulSep/0070.html
https://git.haproxy.org/?p=haproxy.git%3Ba=commit%3Bh=2eab6d354322932cfec2ed54de261e4347eca9a6
https://www.mail-archive.com/haproxy%40formilux.org/msg43861.html

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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.