#VU84442 Uncontrolled Recursion in Squid - CVE-2023-50269

Vulnerability identifier: #VU84442

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2023-50269

CWE-ID: CWE-674

Exploitation vector: Network

Exploit availability: No

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

Vendor: Squid-cache.org

Description

The vulnerability allows a remote client to perform a denial of service (DoS) attack.

The vulnerability exists due to uncontrolled recursion when parsing HTTP requests. A remote client can send a specially crafted HTTP request with the a large X-Forwarded-For header, when the follow_x_forwarded_for feature is configured, and perform a denial of service (DoS) attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Squid: 2.6.stable1 - 2.6, 2.7.stable1 - 2.7, 3.0.stable1 - 3.5.28, 4.0 - 4.17, 5.0 - 5.9, 6.0.1 - 6.5

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External links
https://github.com/squid-cache/squid/security/advisories/GHSA-wgq4-4cfg-c4x3
https://www.squid-cache.org/Versions/v5/SQUID-2023_10.patch
https://www.squid-cache.org/Versions/v6/SQUID-2023_10.patch

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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.