CVE-2026-33526CWE-416CWE-826

Squid vulnerable to Denial of Service in ICP Request handling

Critical · published March 26, 2026

CVSS v4.0
9.2
EPSS
9%
Percentile
95.2
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
9.2 · CRITICAL
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
EPSS
0.08942 · 95.2th percentile
Weaknesses
CWE-416 · Use After Free; CWE-826 · Premature Release of Resource During Expected Lifetime
Published
2026-03-26T00:16Z
EPSS history
Timeline
  • 26 MAR 00:16Z
    Squid vulnerable to Denial of Service in ICP Request handling
    cvelistv5