CVE-2026-33526 — Squid vulnerable to Denial of Service in ICP Request handling

Description (CNA)

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 (CNA)

Vendor / product	Versions
squid-cache / squid	affected < 7.5

CWE

CWE-416, CWE-826

References

ADP enrichment

CVE

No English description supplied.

http://www.openwall.com/lists/oss-security/2026/03/25/2

CISA-ADP

No English description supplied.

No references supplied.

redhat-SADP

A flaw was found in Squid. A remote attacker can exploit a heap Use-After-Free vulnerability when handling ICP (Internet Cache Protocol) traffic. This allows them to perform a reliable and repeatable Denial of Service (DoS) attack, making the Squid service unavailable. This attack is limited to deployments where ICP support is explicitly enabled.