Description
Squid is a caching proxy for the Web. Prior to version 7.5, due to premature release of resource during expected lifetime and heap Use-After-Free bugs, 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. This bug is fixed in Squid version 7.5.
Problem types
CWE-413: Improper Resource Locking
CWE-826: Premature Release of Resource During Expected Lifetime
Product status
References
www.openwall.com/lists/oss-security/2026/03/25/3
github.com/.../squid/security/advisories/GHSA-f9p7-3jqg-hhvq
github.com/...ommit/703e07d25ca6fa11f52d20bf0bb879e22ab7481b