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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HWeakness enumeration
Affected software
| Vendor | Product | Versions |
|---|---|---|
| squid-cache | squid | < 7.5 |
| Red Hat | Red Hat Enterprise Linux 10 | — |
| Red Hat | Red Hat Enterprise Linux 10.0 Extended Update Support | — |
| Red Hat | Red Hat Enterprise Linux 7 Extended Lifecycle Support | — |
| Red Hat | Red Hat Enterprise Linux 8 | — |
| Red Hat | Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | — |
| Red Hat | Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | — |
| Red Hat | Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | — |
| Red Hat | Red Hat Enterprise Linux 8.6 Telecommunications Update Service | — |
| Red Hat | Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions | — |
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | — |
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | — |
| Red Hat | Red Hat Enterprise Linux 9 | — |
| Red Hat | Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions | — |
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | — |
| Red Hat | Red Hat Enterprise Linux 9.4 Extended Update Support | — |
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | — |
| Red Hat | Red Hat Enterprise Linux 6 | — |
| Red Hat | Red Hat Enterprise Linux 6 | — |
References
- https://github.com/squid-cache/squid/commit/8a7d42f9d44befb8fcbbb619505587c8de6a1e91Patch
- https://github.com/squid-cache/squid/security/advisories/GHSA-hpfx-h48q-gvwgVendor Advisory
- http://www.openwall.com/lists/oss-security/2026/03/25/2Third Party Advisory
- https://access.redhat.com/errata/RHSA-2026:10255
- https://access.redhat.com/errata/RHSA-2026:10256
- https://access.redhat.com/errata/RHSA-2026:10257
- https://access.redhat.com/errata/RHSA-2026:11901
- https://access.redhat.com/errata/RHSA-2026:20564
- https://access.redhat.com/errata/RHSA-2026:20565
- https://access.redhat.com/errata/RHSA-2026:20580
- https://access.redhat.com/errata/RHSA-2026:6301
- https://access.redhat.com/errata/RHSA-2026:8119
- https://access.redhat.com/errata/RHSA-2026:8317
- https://access.redhat.com/errata/RHSA-2026:8880
- https://access.redhat.com/errata/RHSA-2026:9220
- https://access.redhat.com/security/cve/CVE-2026-33526
- https://bugzilla.redhat.com/show_bug.cgi?id=2451574
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33526.json
Timeline
- Published
- Mar 26, 2026
- Last modified
- Jul 15, 2026
- NVD status
- Modified