Vulnerability identifier: #VU84442

Vulnerability risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

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: 6.0.1 - 6.5, 5.0 - 5.9, 4.0 - 4.17, 3.0 - 3.5.28, 2.7 - 2.7.STABLE9, 2.6 - 2.6.stable24

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