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.
CVSS Details
- CVSS 4.0 Base Score: 9.2 (CRITICAL)
- CVSS 4.0 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)
- CVSS 3.1 Base Score: 7.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade libecapUpgrade libecap-develUpgrade squid | Apr 2, 2026 | Mar 31, 2026 |
| Amazon Linux Ami 2 | — | Upgrade squidUpgrade squid-debuginfoUpgrade squid-migration-scriptUpgrade squid-sysvinit | May 20, 2026 | May 20, 2026 |
| Amazon_linux_2023 | — | Upgrade squidUpgrade squid-debuginfoUpgrade squid-debugsource | Apr 14, 2026 | Mar 26, 2026 |
| Debian | — | Upgrade squid | Jul 23, 2026 | Jul 23, 2026 |
| Oracle_linux | — | Upgrade squidUpgrade libecap-develUpgrade squid-sysvinitUpgrade squid-migration-scriptUpgrade libecap | Apr 2, 2026 | Mar 26, 2026 |
| Redhat_linux | — | No solution existsUpgrade squid-debugsourceUpgrade squid-sysvinitUpgrade squid-migration-scriptUpgrade squid-debuginfoUpgrade libecap-debugsourceUpgrade squidUpgrade libecap-develUpgrade libecapUpgrade libecap-debuginfo | Apr 6, 2026 | Mar 26, 2026 |
| Rocky_linux | — | Upgrade squid-debugsourceUpgrade libecapUpgrade squid-debuginfoUpgrade libecap-debuginfoUpgrade libecap-debugsourceUpgrade libecap-develUpgrade squid | Apr 8, 2026 | Apr 7, 2026 |
| Ubuntu | — | Upgrade squid | Apr 9, 2026 | Apr 8, 2026 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | May 27, 2026 | Mar 26, 2026 |
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