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CentOS Linux 6 [TuxCare] Security Update: spamassassin Multiple Vulnerabilities (CENTOS6:CLSA-2026:1777548877)

high Nessus Plugin ID 359563

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-2026:1777548877 advisory.

 - A denial of service vulnerability was identified that exists in Apache SpamAssassin before 3.4.2. The vulnerability arises with certain unclosed tags in emails that cause markup to be handled incorrectly leading to scan timeouts. In Apache SpamAssassin, using HTML::Parser, we setup an object and hook into the begin and end tag event handlers In both cases, the open event is immediately followed by a close event - even if the tag *does not* close in the HTML being parsed. Because of this, we are missing the text event to deal with the object normally. This can cause carefully crafted emails that might take more scan time than expected leading to a Denial of Service. The issue is possibly a bug or design decision in HTML::Parser that specifically impacts the way Apache SpamAssassin uses the module with poorly formed html. The exploit has been seen in the wild but not believed to have been purposefully part of a Denial of Service attempt. We are concerned that there may be attempts to abuse the vulnerability in the future. (CVE-2017-15705)

 - Apache SpamAssassin 3.4.2 fixes a local user code injection in the meta rule syntax. (CVE-2018-11781)

 - In Apache SpamAssassin before 3.4.3, nefarious CF files can be configured to run system commands without any output or errors. With this, exploits can be injected in a number of scenarios. In addition to upgrading to SA 3.4.3, we recommend that users should only use update channels or 3rd party .cf files from trusted places. (CVE-2018-11805)

 - In Apache SpamAssassin before 3.4.3, a message can be crafted in a way to use excessive resources.
 Upgrading to SA 3.4.3 as soon as possible is the recommended fix but details will not be shared publicly.
 (CVE-2019-12420)

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 spamassassin package based on the guidance in TuxCare advisory CENTOS6:CLSA-2026:1777548877.

See Also

https://cve.tuxcare.com/els/releases/CLSA-2026:1777548877

http://www.nessus.org/u?9848e7f7

Plugin Details

Severity: High

ID: 359563

File Name: tuxcare_centos_6_CLSA-2026-1777548877.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 10/1/2026

Updated: 10/1/2026

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

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 57.12

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: High

Base Score: 7.2

Temporal Score: 5.3

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

CVSS Score Source: CVE-2018-11805

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

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

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

CVSS Score Source: CVE-2018-11781

Vulnerability Information

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

Exploit Ease: No known exploits are available

Patch Publication Date: 4/30/2026

Vulnerability Publication Date: 9/16/2018

Reference Information

CVE: CVE-2017-15705, CVE-2018-11781, CVE-2018-11805, CVE-2019-12420

CLSA: 2026:1777548877