CVE-2020-4082: 
NixOS vulnerability analysis and mitigation

A security update was released for Squid, a high-performance proxy caching server for web clients. The update addresses multiple vulnerabilities discovered in 2020, including HTTP Request Smuggling, HTTP Request Splitting, and Information Disclosure issues (Red Hat Advisory).

The vulnerability affects Squid version 3.5.20 and includes multiple security issues: HTTP Request Smuggling (CVE-2020-15810), HTTP Request Splitting (CVE-2020-15811), Information Disclosure in FTP Gateway (CVE-2019-12528), Improper input validation in HTTP Request processing (CVE-2020-8449), Buffer overflow in reverse-proxy configurations (CVE-2020-8450), Request smuggling and poisoning attack against the HTTP cache (CVE-2020-15049), and Improper input validation leading to DoS (CVE-2020-24606) (Red Hat Advisory).

The vulnerabilities could result in cache poisoning, information disclosure, buffer overflow in reverse-proxy configurations, and denial of service conditions (Red Hat Advisory).

Red Hat has released security updates to address these vulnerabilities. After installing the update, the squid service will be restarted automatically. The fix is available through package update squid-3.5.20-17.el7_9.4 for affected systems (Red Hat Advisory).