CVE-2026-33526

CRITICAL EPSS 84.3%
Published Mar 26, 20263mo ago · Modified Jun 17, 20262w ago
9.2 CVSS 4.0
Critical
Find Similar
Published Mar 26, 2026 3mo ago
Last Modified Jun 17, 2026 2w ago

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 Details

Base Score
9.2
Exploitability
—
Impact
—
Vector string
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
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope X

Threat Intelligence

EPSS Exploit Probability
84.3% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 2

CWE-416 Use After Free Memory Safety
CWE-826

Affected Products 1

VendorProductVersionRange
squid-cachesquid* <7.5

References 3

  • openwall.com http://www.openwall.com/lists/oss-security/2026/03/25/2
    Third Party Advisory
  • github.com https://github.com/squid-cache/squid/commit/8a7d42f9d44befb8fcbbb619505587c8de6a1e91
    Patch
  • github.com https://github.com/squid-cache/squid/security/advisories/GHSA-hpfx-h48q-gvwg
    Vendor Advisory

Remediation

  • github.com https://github.com/squid-cache/squid/commit/8a7d42f9d44befb8fcbbb619505587c8de6a1e91
    Patch