Amazon Linux 2 : squid, --advisory ALAS2-2026-3242 (ALAS-2026-3242)

critical Nessus Plugin ID 306300

Synopsis

The remote Amazon Linux 2 host is missing a security update.

Description

The version of squid installed on the remote host is prior to 3.5.20-17. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2026-3242 advisory.

Squid is a caching proxy for the Web. Prior to version 7.5, due to premature release of resource during expected lifetime and heap Use-After-Free bugs, 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. This bug is fixed in Squid version 7.5.

NOTE: https://www.openwall.com/lists/oss-security/2026/03/25/3NOTE: Fixed by: https://github.com/squid- cache/squid/commit/703e07d25ca6fa11f52d20bf0bb879e22ab7481b (SQUID_7_5) (CVE-2026-32748)

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.

NOTE: https://www.openwall.com/lists/oss-security/2026/03/25/2NOTE: Fixed by: https://github.com/squid- cache/squid/commit/8a7d42f9d44befb8fcbbb619505587c8de6a1e91 (SQUID_7_5) (CVE-2026-33526)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Run 'yum update squid' or or 'yum update --advisory ALAS2-2026-3242' to update your system.

Plugin Details

Severity: Critical

ID: 306300

File Name: al2_ALAS-2026-3242.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 4/14/2026

Updated: 4/14/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2026-33526

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

CVSS v4

Risk Factor: Critical

Base Score: 9.2

Threat Score: 7.7

Threat Vector: CVSS:4.0/E:U

Vector: 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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:squid-sysvinit, p-cpe:/a:amazon:linux:squid-migration-script, p-cpe:/a:amazon:linux:squid-debuginfo, cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:squid

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 4/14/2026

Vulnerability Publication Date: 3/26/2026

Reference Information

CVE: CVE-2026-32748, CVE-2026-33526

IAVB: 2026-B-0076

Detections

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