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CVE-2026-33526

Squid vulnerable to Denial of Service in ICP Request handling

Published: Mar 26, 2026Updated: Mar 31, 2026 Sources: CVE List NVD BDUCWE-416
NVD MITRE
7.5CVSSHIGH
EPSS Score
2.7%
Top 15.8%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
Open in CVSS calculator →

Weaknesses

CWE-416CWE-826

Affected Products

squidsquid-cache
On-premNetwork Device
Networking Infrastructure / load-balancer-proxy
Red Hat Enterprise LinuxRed Hat Inc.
On-premOS
Operating Systems / linux-distro
РЕД ОСООО «Ред Софт»
On-premOS
Operating Systems / linux-distro
SquidSquid Software Foundation
On-premNetwork Device
Networking Infrastructure / load-balancer-proxy
squid-cacheoss-projectNetworking Infrastructureaka squid, squid cache
red hat inc.commercialUSOperating Systemsaka red hat
ооо «ред софт»commercialRUOperating Systemsaka red soft
squid software foundationoss-projectNetworking Infrastructure

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

2 techniques
Initial Access
Privilege Escalation
View detailed technique mapping

References

https://github.com/squid-cache/squid/commit/8a7d42f9d44befb8fcbbb619505587c8de6a1e91
github.com
https://github.com/squid-cache/squid/security/advisories/GHSA-hpfx-h48q-gvwg
github.com
http://www.openwall.com/lists/oss-security/2026/03/25/2
openwall.com
and 5 more references View all →

Timeline

Published
Mar 26, 2026
Last Updated
Mar 31, 2026

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