SB2026040935 - Ubuntu update for squid
Published: April 9, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 3 vulnerabilities.
1) Use After Free (CVE-ID: CVE-2026-33526)
CWE-ID: CWE-416 - Use After Free
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to heap use-after-free in ICP request handling when processing ICP traffic. A remote attacker can send a specially crafted ICP request to cause a denial of service.
The attack is limited to Squid deployments that have ICP support enabled via a non-zero icp_port configuration.
2) Out-of-bounds read (CVE-ID: CVE-2026-33515)
CWE-ID: CWE-125 - Out-of-bounds read
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to improper input validation in ICP message handling when processing ICP traffic. A remote attacker can send a specially crafted ICP request to disclose small amounts of memory potentially containing sensitive information.
The attack is limited to Squid deployments that explicitly enable ICP support (i.e., configure a non-zero icp_port).
3) Use After Free (CVE-ID: CVE-2026-32748)
CWE-ID: CWE-416 - Use After Free
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to use-after-free in ICP request handling when processing ICP traffic. A remote attacker can send a specially crafted ICP request to cause a denial of service.
The vulnerability is only exploitable on Squid deployments that have ICP support enabled via a non-zero icp_port configuration.
Remediation
Install update from vendor's website.