# CVE-2026-33526

## Summary

- **CVE ID:** CVE-2026-33526
- **Severity:** CRITICAL
- **CVSS Score:** 9.2 (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)
- **CWE:** CWE-416, CWE-826
- **Published:** Mar 26, 2026
- **Last Modified:** Jul 15, 2026

## 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.

## Affected Products

- squid-cache — squid (< 7.5)

## References

- [CNA](https://github.com/squid-cache/squid/security/advisories/GHSA-hpfx-h48q-gvwg)
- [CNA](https://github.com/squid-cache/squid/commit/8a7d42f9d44befb8fcbbb619505587c8de6a1e91)
- [CVE](http://www.openwall.com/lists/oss-security/2026/03/25/2)
- [redhat-SADP](https://access.redhat.com/security/cve/CVE-2026-33526)
- [redhat-SADP](https://bugzilla.redhat.com/show_bug.cgi?id=2451574)
- [redhat-SADP](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33526.json)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:8880)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:11901)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:8119)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:8317)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:20564)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:20565)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:20580)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:10256)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:10257)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:10255)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:9220)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:6301)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 8.94%
- **EPSS Percentile:** 94.9

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._