CVE-2026-33526: Squid-Cache Squid

High severity, CVSS 7.5. EPSS: 12.8% chance of exploitation in the next 30 days.

Squid is a caching proxy for the Web. Prior to version 7.5, due to heap Use-After-Free, Squid is vulnerable to Denial of Service when handling ICP traffic. This problem allows a remote attacker to perform a reliable and repeatable Denial of Service attack against the Squid service using ICP protocol. This attack is limited to Squid deployments that explicitly enable ICP support (i.e. configure non-zero `icp_port`). This problem _cannot_ be mitigated by denying ICP queries using `icp_access` rules. Version 7.5 contains a patch.

Affected products

• Squid-Cache Squid: before 7.5 (fixed in 7.5)

Published 2026-03-26. Last modified 2026-07-15.