CVE-2026-33526
Squid vulnerable to Denial of Service in ICP Request handling
- State
- Published
- Severity
- 9.2 Critical
- Published
- Mar 26, 2026
- Updated
- Jul 15, 2026
- Reserved
- Mar 20, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 9.2 Critical | 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 | GitHub_M |
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | redhat-SADP |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
squidsquid-cache |
|
References
- https://github.com/squid-cache/squid/security/advisories/GHSA-hpfx-h48q-gvwg
- https://github.com/squid-cache/squid/commit/8a7d42f9d44befb8fcbbb619505587c8de6a1e91
- http://www.openwall.com/lists/oss-security/2026/03/25/2
- https://access.redhat.com/security/cve/CVE-2026-33526vdb-entry
- RHBZ#2451574issue-tracking
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33526.json
- https://access.redhat.com/errata/RHSA-2026:8880vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:11901vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:8119vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:8317vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:20564vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:20565vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:20580vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:10256vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:10257vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:10255vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:9220vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:6301vendor-advisory
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