Squid has Denial of Service in ICP Response handling
Summary
| CVE | CVE-2026-32748 |
|---|---|
| State | PUBLISHED |
| Assigner | GitHub_M |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-03-26 01:16:26 UTC |
| Updated | 2026-06-30 03:18:34 UTC |
| Description | Squid is a caching proxy for the Web. Prior to version 7.5, due to premature release of resource during expected lifetime and heap Use-After-Free bugs, 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. This bug is fixed in Squid version 7.5. |
Risk And Classification
Primary CVSS: v4.0 8.7 HIGH from [email protected]
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/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
EPSS: 0.089310000 probability, percentile 0.946060000 (date 2026-07-02)
Problem Types: CWE-413 | CWE-416 | CWE-826 | CWE-413 CWE-413: Improper Resource Locking | CWE-416 CWE-416: Use After Free | CWE-826 CWE-826: Premature Release of Resource During Expected Lifetime | CWE-826 Premature Release of Resource During Expected Lifetime
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 8.7 | HIGH | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/C... |
| 4.0 | CNA | DECLARED | 8.7 | HIGH | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L |
| 3.1 | [email protected] | Primary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | ADP | CVSS | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | Secondary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
CVSS v4.0 Breakdown
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/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 v3.1 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Application | Squid-cache | Squid | All | All | All | All |
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| access.redhat.com/errata/RHSA-2026:8880 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| bugzilla.redhat.com/show_bug.cgi | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | bugzilla.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-32748 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:20580 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:10256 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| github.com/squid-cache/squid/security/advisories/GHSA-f9p7-3jqg-hhvq | [email protected] | github.com | Mitigation, Patch, Vendor Advisory |
| access.redhat.com/errata/RHSA-2026:8119 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:20565 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:11901 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:10255 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:6301 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:20564 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| www.openwall.com/lists/oss-security/2026/03/25/3 | af854a3a-2127-422b-91ae-364da2661108 | www.openwall.com | Mailing List, Mitigation, Patch, Third Party Advisory |
| security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-32748.json | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | security.access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:9220 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| github.com/squid-cache/squid/commit/703e07d25ca6fa11f52d20bf0bb879e22ab7... | [email protected] | github.com | Patch |
| access.redhat.com/errata/RHSA-2026:8317 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:10257 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| ADP | 2026-03-26T01:01:29.920Z | Reported to Red Hat. |
| ADP | 2026-03-26T00:11:01.424Z | Made public. |
Solutions
ADP: RHSA-2026:8880: Red Hat Enterprise Linux Server (v. 7 ELS)
ADP: RHSA-2026:11901: Red Hat Enterprise Linux AppStream EUS (v. 10.0)
ADP: RHSA-2026:8119: Red Hat Enterprise Linux AppStream (v. 10)
ADP: RHSA-2026:8317: Red Hat Enterprise Linux AppStream (v. 8)
ADP: RHSA-2026:20564: Red Hat Enterprise Linux AppStream AUS (v.8.4), Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4)
ADP: RHSA-2026:20565: Red Hat Enterprise Linux AppStream AUS (v.8.6), Red Hat Enterprise Linux AppStream E4S (v.8.6), Red Hat Enterprise Linux AppStream TUS (v.8.6)
ADP: RHSA-2026:20580: Red Hat Enterprise Linux AppStream E4S (v.8.8), Red Hat Enterprise Linux AppStream TUS (v.8.8)
ADP: RHSA-2026:10256: Red Hat Enterprise Linux AppStream E4S (v.9.0)
ADP: RHSA-2026:10257: Red Hat Enterprise Linux AppStream E4S (v.9.2)
ADP: RHSA-2026:10255: Red Hat Enterprise Linux AppStream EUS (v.9.4)
ADP: RHSA-2026:9220: Red Hat Enterprise Linux AppStream EUS (v.9.6)
ADP: RHSA-2026:6301: Red Hat Enterprise Linux AppStream (v. 9)
Workarounds
ADP: To mitigate this issue, ensure that ICP support is not explicitly enabled in the Squid configuration. This can be achieved by commenting out or setting `icp_port` to `0` in the `squid.conf` file. After modifying the configuration, the Squid service must be reloaded or restarted for the changes to take effect. Example: ``` # icp_port 3130 ``` or ``` icp_port 0 ``` Warning: Reloading or restarting the Squid service may temporarily interrupt proxy services.