Squid

Squid at a glance

Squid is a widely used open-source caching and forwarding web proxy, common for web filtering, caching and access control in networks. Squid ships regular releases plus coordinated security fixes; as a proxy that parses untrusted web traffic, its advisories deserve prompt attention.

For admins Squid usually comes from the distribution, which backports fixes — and Squid has had a notably steady stream of security advisories (many in HTTP parsing), so confirm the patched package is installed and the service restarted. Harden the configuration: restrict who can use the proxy (avoid an open proxy), scope ACLs tightly, and mind TLS interception if used (it has privacy and security implications). Keep the version and its support branch in view. After updating, verify that proxying and filtering still work. Because it sits in the web path for many clients, treat its advisories seriously. Patchletter surfaces new Squid releases.