CVE-2026-33526

Name: CVE-2026-33526
Creator: NVD / NIST
Published: 2026-03-26T01:16:27.877+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.2/10EPSS 2.74%

Last modified Jun 17, 2026

CVE-2026-33526 is a critical-severity vulnerability rated 9.2/10 on the CVSS scale. 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. EPSS estimates a 2.74% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS 4.0

9.2/10

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

EPSS Probability

2.74%

84.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Squid-Cache	Squid	< 7.5

References

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

Timeline

Published: Mar 26, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-33526?

How severe is CVE-2026-33526?

CVE-2026-33526 has a CVSS score of 9.2/10 (CRITICAL severity). The EPSS model estimates a 2.74% probability of exploitation in the next 30 days.

How do I fix CVE-2026-33526?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-33526?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST