CVE-2020-8449: 
Squid vulnerability analysis and mitigation

CVE-2020-8449 was discovered in Squid versions before 4.10, disclosed in February 2020. The vulnerability stems from incorrect input validation that allows Squid to interpret crafted HTTP requests in unexpected ways to access server resources prohibited by earlier security filters. This vulnerability specifically affects Squid installations acting as reverse-proxy (Squid Advisory, NVD).

The vulnerability arises from improper input validation in HTTP request processing when Squid is configured with http_port 'accel' or 'vhost' options. The issue allows Squid to interpret crafted HTTP requests in ways that bypass previously implemented security filters. The vulnerability has been assigned a CVSS score of 7.5 (HIGH) with a vector of CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N (NetApp Advisory).

Successful exploitation of this vulnerability could lead to unauthorized access to server resources that were meant to be restricted by security filters. The vulnerability potentially allows attackers to bypass security access controls in systems between client and proxy, and could result in information disclosure or modification of data (Squid Advisory, Ubuntu Notice).

The vulnerability was fixed in Squid version 4.10. For earlier versions, there are no workarounds available, and users are advised to upgrade to version 4.10 or later. Various Linux distributions have released security updates to address this vulnerability, including Ubuntu, Debian, Fedora, and Gentoo (Gentoo Advisory, Ubuntu Notice).