CVE-2026-33526
High
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.
SeverityHigh
CVSS7.5
Exploit probability—
ProductSquid
PublishedMar 26, 2026
First seenMar 26, 2026
Weakness typeCWE-416Use after freeCWE-826CWE-826
How to fix
Update
- squid-cache squid7.5 or later
Vendor advisories
- access.redhat.com/errata/RHSA-2026:8880
- access.redhat.com/errata/RHSA-2026:11901
- access.redhat.com/errata/RHSA-2026:8119
- access.redhat.com/errata/RHSA-2026:8317
- access.redhat.com/errata/RHSA-2026:20564
- access.redhat.com/errata/RHSA-2026:20565
- access.redhat.com/errata/RHSA-2026:20580
- access.redhat.com/errata/RHSA-2026:10256
- access.redhat.com/errata/RHSA-2026:10257
- access.redhat.com/errata/RHSA-2026:10255
- access.redhat.com/errata/RHSA-2026:9220
- access.redhat.com/errata/RHSA-2026:6301
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| squid-cache squid | v < 7.5 | 7.5 |
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