CVE-2026-33526

Advisory lineage Upstream: 0 Downstream: 1
Received
Published: 26 Mar 2026, 00:16
Last modified:26 Mar 2026, 00:24

Vulnerability Summary

Overall Risk (default)
high
70/100
CVSS Score
9.2 CRITICAL
v4.0 (cve.org)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

26 Mar 2026, 00:16
Published
Vulnerability first disclosed
26 Mar 2026, 00:24
Last Modified
Vulnerability information updated

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 Metrics

  • v4.0•CRITICAL•Score: 9.2CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
  • v4.0•CRITICAL•Score: 9.2CVSS: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

Techniques & Countermeasures

  • CWE-416•Use After Free

    The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

  • CWE-826•Premature Release of Resource During Expected Lifetime

    The product releases a resource that is still intended to be used by itself or another actor.

Affected Systems

  • squid-cache•squid

    < 7.5

References (3)