CVE-2026-33526
March 26, 2026
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.
Affected Packages
https://github.com/squid-cache/squid.git (GITHUB):
Affected version(s) >=SQUID_3_0_RC1 <SQUID_7_5Fix Suggestion:
Update to version SQUID_7_5https://github.com/squid-cache/squid.git (GITHUB):
Affected version(s) >=SQUID_3_0_RC1 <SQUID_7_5Fix Suggestion:
Update to version SQUID_7_5https://github.com/squid-cache/squid.git (GITHUB):
Affected version(s) >=SQUID_3_0_RC1 <SQUID_7_5Fix Suggestion:
Update to version SQUID_7_5Additional Notes
The description of this vulnerability differs from MITRE.
Related Resources (3)
Do you need more information?
Contact UsCVSS v4
Base Score:
9.2
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
HIGH
CVSS v3
Base Score:
8.6
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
EPSS
Base Score:
1.98
