Home/CVE/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
CVE

CVE-2026-33526

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

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.

HIGH · CVSS 7.5 EPSS 0.01395
Schedule remediation
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-416Use After Free
CWE-826Premature Release of Resource During Expected Lifetime
▤

Affected Products & Versions

1
squid-cache squid< 7.5
▣

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD26 Mar 2026 · 01:16 AM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

14
usnUSN-8157-1
msrcCVE-2026-33526
rhsaRHSA-2026:8880Important
rhsaRHSA-2026:9220Important
rhsaRHSA-2026:11901Important
🔗

References & Sources

3
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/squid-cache/squid/commit/8a7d42f9d44befb8fcbbb619505587c8de6a1e91Patch
https://github.com/squid-cache/squid/security/advisories/GHSA-hpfx-h48q-gvwgVendor Advisory
http://www.openwall.com/lists/oss-security/2026/03/25/2Third Party Advisory
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