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CentOS Linux 6 [TuxCare] Security Update: sendmail / sendmail-cf / sendmail-devel / sendmail-doc / etc (CENTOS6:CLSA-2026:1793168965)

high Nessus Plugin ID 374853

Synopsis

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

Description

The CentOS Linux 6 host has packages installed that are affected by a vulnerability as referenced in the TuxCare CENTOS6:CLSA-2026:1793168965 advisory.

 - ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross- protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer. (CVE-2021-3618)

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

Solution

Update the affected packages based on the guidance in TuxCare advisory CENTOS6:CLSA-2026:1793168965.

See Also

https://cve.tuxcare.com/els/releases/CLSA-2026:1793168965

http://www.nessus.org/u?01bccfe8

Plugin Details

Severity: High

ID: 374853

File Name: tuxcare_centos_6_CLSA-2026-1793168965.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 11/1/2026

Updated: 11/1/2026

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

Risk Information

VPR

Risk Factor: Medium

Score: 4.3

Percentile: 53.59

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: Medium

Base Score: 5.8

Temporal Score: 4.3

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

CVSS Score Source: CVE-2021-3618

CVSS v3

Risk Factor: High

Base Score: 7.4

Temporal Score: 6.4

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

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

Vulnerability Information

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

Exploit Ease: No known exploits are available

Patch Publication Date: 10/28/2026

Vulnerability Publication Date: 9/24/2021

Reference Information

CVE: CVE-2021-3618

CLSA: 2026:1793168965