CentOS Linux 6 [TuxCare] Security Update: squid34 Multiple Vulnerabilities (CENTOS6:CLSA-2026:1787042235)

critical Nessus Plugin ID 359908

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Synopsis

The CentOS Linux host is missing one or more security updates.

Description

The CentOS Linux 6 host has a package installed that is affected by multiple vulnerabilities as referenced in the TuxCare CENTOS6:CLSA-2026:1787042235 advisory.

- An issue was discovered in Squid before 4.9. URN response handling in Squid suffers from a heap-based buffer overflow. When receiving data from a remote server in response to an URN request, Squid fails to ensure that the response can fit within the buffer. This leads to attacker controlled data overflowing in the heap. (CVE-2019-12526)

- Squid is a caching proxy for the Web. Prior to 7.6, due to an improper validation of syntactic correctness of input in the FTP gateway (src/clients/FtpGateway.cc), Squid is vulnerable to an out-of-bounds read:
when a listing entry date in the TypeA or TypeB directory-listing formats is not followed by a filename, parsing was not restricted to the input buffer, so a trusted client accessing a misbehaving FTP server through Squid's gateway feature could read memory from random unrelated transactions. This issue is fixed in version 7.6. (CVE-2026-47729)

- Squid is a caching proxy for the Web. Prior to 7.6, due to an improper input validation bug in cache digest reply handling (peerDigestSwapInMask in src/peer_digest.cc), Squid is vulnerable to a heap-based buffer overflow: a cache digest's on-the-wire size may be larger than the mask_size declared within the digest, so a trusted peer sending a maliciously crafted reply to a cache_digest request message can trigger the overflow. This attack is limited to Squid instances compiled with the --enable-cache-digests option and configured with cache_peer entries. This issue is fixed in version 7.6. (CVE-2026-50012)

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

Solution

Update the affected squid34 package based on the guidance in TuxCare advisory CENTOS6:CLSA-2026:1787042235.

Plugin Details

Severity: Critical

ID: 359908

File Name: tuxcare_centos_6_CLSA-2026-1787042235.nasl

Version: 1.2

Type: Local

Agent: unix

Family: CentOS Local Security Checks

Published: 10/1/2026

Updated: 10/28/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.2

Percentile: 96.1

Vendor

Vendor Severity: Moderate

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 5.9

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

CVSS Score Source: CVE-2019-12526

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.8

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

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

Vulnerability Information

Required KB Items: Host/local_checks_enabled, Host/CentOS/release, Host/CentOS/rpm-list, Host/OS/extended-third-party

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 8/18/2026

Vulnerability Publication Date: 6/18/2026

Reference Information

CVE: CVE-2019-12526, CVE-2026-47729, CVE-2026-50012

CLSA: 2026:1787042235

Detections

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