Linux Distros Unpatched Vulnerability : CVE-2021-3618

high Nessus Plugin ID 224103

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Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

- 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 relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

Plugin Details

Severity: High

ID: 224103

File Name: unpatched_CVE_2021_3618.nasl

Version: 1.5

Type: local

Agent: unix

Family: Misc.

Published: 3/5/2025

Updated: 9/14/2025

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5.2

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

CPE: cpe:/o:centos:centos:8, p-cpe:/a:centos:centos:sendmail-milter, p-cpe:/a:canonical:ubuntu_linux:sendmail, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, cpe:/o:debian:debian_linux:11.0, p-cpe:/a:redhat:enterprise_linux:sendmail-milter-devel, p-cpe:/a:centos:centos:nginx-mod-mail, p-cpe:/a:centos:centos:nginx-mod-http-xslt-filter, p-cpe:/a:redhat:enterprise_linux:nginx-mod-mail, p-cpe:/a:centos:centos:nginx-all-modules, p-cpe:/a:redhat:enterprise_linux:nginx-mod-stream, p-cpe:/a:centos:centos:nginx-filesystem, p-cpe:/a:redhat:enterprise_linux:sendmail-cf, cpe:/o:redhat:enterprise_linux:8, p-cpe:/a:centos:centos:sendmail-doc, p-cpe:/a:redhat:enterprise_linux:nginx-mod-devel, p-cpe:/a:redhat:enterprise_linux:nginx-filesystem, p-cpe:/a:debian:debian_linux:vsftpd, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:centos:centos:sendmail-milter-devel, p-cpe:/a:centos:centos:nginx-mod-devel, p-cpe:/a:redhat:enterprise_linux:sendmail-milter, p-cpe:/a:canonical:ubuntu_linux:nginx, p-cpe:/a:canonical:ubuntu_linux:vsftpd, p-cpe:/a:centos:centos:sendmail, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:redhat:enterprise_linux:sendmail, p-cpe:/a:redhat:enterprise_linux:nginx-all-modules, p-cpe:/a:centos:centos:vsftpd, p-cpe:/a:redhat:enterprise_linux:vsftpd, cpe:/o:canonical:ubuntu_linux:14.04:-:lts, p-cpe:/a:debian:debian_linux:sendmail, p-cpe:/a:redhat:enterprise_linux:nginx-mod-http-image-filter, p-cpe:/a:redhat:enterprise_linux:sendmail-doc, p-cpe:/a:redhat:enterprise_linux:nginx-mod-http-perl, p-cpe:/a:centos:centos:sendmail-cf, p-cpe:/a:redhat:enterprise_linux:nginx-mod-http-xslt-filter, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:centos:centos:nginx-mod-http-image-filter, cpe:/o:debian:debian_linux:12.0, p-cpe:/a:centos:centos:nginx-mod-stream, p-cpe:/a:centos:centos:nginx-mod-http-perl

Required KB Items: Host/local_checks_enabled, Host/cpu, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 10/25/2021

Reference Information

CVE: CVE-2021-3618

Detections

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