Bug 2451574 (CVE-2026-33526)

Summary:	CVE-2026-33526 squid: Squid: Denial of Service via heap Use-After-Free vulnerability in ICP handling
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	Keywords:	Security
Target Milestone:	---
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in Squid. A remote attacker can exploit a heap Use-After-Free vulnerability when handling ICP (Internet Cache Protocol) traffic. This allows them to perform a reliable and repeatable Denial of Service (DoS) attack, making the Squid service unavailable. This attack is limited to deployments where ICP support is explicitly enabled.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2451598, 2451599
Bug Blocks:

Description OSIDB Bzimport 2026-03-26 01:01:40 UTC

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.

Comment 2 errata-xmlrpc 2026-03-31 20:03:41 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:6301 https://access.redhat.com/errata/RHSA-2026:6301

Comment 3 errata-xmlrpc 2026-04-14 15:05:09 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:8119 https://access.redhat.com/errata/RHSA-2026:8119

Comment 4 errata-xmlrpc 2026-04-15 14:29:47 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:8317 https://access.redhat.com/errata/RHSA-2026:8317

Comment 5 errata-xmlrpc 2026-04-20 03:38:24 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7 Extended Lifecycle Support

Via RHSA-2026:8880 https://access.redhat.com/errata/RHSA-2026:8880

Comment 6 errata-xmlrpc 2026-04-21 06:04:06 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.6 Extended Update Support

Via RHSA-2026:9220 https://access.redhat.com/errata/RHSA-2026:9220

Comment 7 errata-xmlrpc 2026-04-23 23:04:38 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Via RHSA-2026:10257 https://access.redhat.com/errata/RHSA-2026:10257

Comment 8 errata-xmlrpc 2026-04-23 23:08:09 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions

Via RHSA-2026:10256 https://access.redhat.com/errata/RHSA-2026:10256

Comment 9 errata-xmlrpc 2026-04-24 01:02:59 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Extended Update Support

Via RHSA-2026:10255 https://access.redhat.com/errata/RHSA-2026:10255

Comment 12 errata-xmlrpc 2026-04-29 20:22:49 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10.0 Extended Update Support

Via RHSA-2026:11901 https://access.redhat.com/errata/RHSA-2026:11901

Comment 13 errata-xmlrpc 2026-05-26 03:45:40 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.6 Telecommunications Update Service

Via RHSA-2026:20565 https://access.redhat.com/errata/RHSA-2026:20565

Comment 14 errata-xmlrpc 2026-05-26 04:20:07 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.8 Telecommunications Update Service

Via RHSA-2026:20580 https://access.redhat.com/errata/RHSA-2026:20580

Comment 15 errata-xmlrpc 2026-05-26 05:12:22 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On

Via RHSA-2026:20564 https://access.redhat.com/errata/RHSA-2026:20564