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Linux Distros Unpatched Vulnerability : CVE-2021-20196

medium Nessus Plugin ID 223664

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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.

 - A NULL pointer dereference flaw was found in the floppy disk emulator of QEMU. This issue occurs while processing read/write ioport commands if the selected floppy drive is not initialized with a block device.
 This flaw allows a privileged guest user to crash the QEMU process on the host, resulting in a denial of service. The highest threat from this vulnerability is to system availability. (CVE-2021-20196)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

See Also

https://access.redhat.com/security/cve/cve-2021-20196

https://ubuntu.com/security/CVE-2021-20196

Plugin Details

Severity: Medium

ID: 223664

File Name: unpatched_CVE_2021_20196.nasl

Version: 1.5

Type: local

Agent: unix

Family: Misc.

Published: 3/4/2025

Updated: 9/15/2025

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: Low

Base Score: 2.1

Temporal Score: 1.6

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

CVSS Score Source: CVE-2021-20196

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 5.9

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

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

Vulnerability Information

CPE: p-cpe:/a:redhat:enterprise_linux:qemu-guest-agent, p-cpe:/a:redhat:enterprise_linux:qemu-kvm-rhev, cpe:/o:centos:centos:8, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, p-cpe:/a:centos:centos:libcacard, p-cpe:/a:redhat:enterprise_linux:libcacard-devel, p-cpe:/a:redhat:enterprise_linux:qemu-kvm-common-rhev, p-cpe:/a:centos:centos:qemu-kvm-block-ssh, p-cpe:/a:centos:centos:qemu-kvm-ui-opengl, p-cpe:/a:centos:centos:qemu-kvm-common, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, p-cpe:/a:redhat:enterprise_linux:qemu-kvm-core, cpe:/o:centos:centos:7, p-cpe:/a:centos:centos:qemu-kvm-block-gluster, p-cpe:/a:centos:centos:qemu-kiwi, p-cpe:/a:redhat:enterprise_linux:libcacard, p-cpe:/a:centos:centos:libcacard-tools, p-cpe:/a:centos:centos:qemu-guest-agent, p-cpe:/a:centos:centos:qemu-kvm-hw-usbredir, p-cpe:/a:redhat:enterprise_linux:qemu-img, cpe:/o:redhat:enterprise_linux:8, p-cpe:/a:redhat:enterprise_linux:qemu-kvm-block-iscsi, p-cpe:/a:redhat:enterprise_linux:qemu-kvm-docs, p-cpe:/a:centos:centos:qemu-img, p-cpe:/a:centos:centos:qemu-kvm-block-iscsi, p-cpe:/a:centos:centos:qemu-kvm-common-rhev, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:25.04, p-cpe:/a:redhat:enterprise_linux:qemu-kvm-hw-usbredir, cpe:/o:redhat:enterprise_linux:7, p-cpe:/a:canonical:ubuntu_linux:xen, p-cpe:/a:centos:centos:qemu-kvm-rhev, p-cpe:/a:redhat:enterprise_linux:qemu-kvm-tests, p-cpe:/a:redhat:enterprise_linux:qemu-kvm-tools-rhev, p-cpe:/a:redhat:enterprise_linux:qemu-img-rhev, p-cpe:/a:redhat:enterprise_linux:qemu-kvm-block-gluster, p-cpe:/a:centos:centos:qemu-kvm-tests, p-cpe:/a:redhat:enterprise_linux:qemu-kvm-common, p-cpe:/a:redhat:enterprise_linux:qemu-kiwi, p-cpe:/a:centos:centos:qemu-kvm-tools-rhev, cpe:/a:redhat:advanced_virtualization:8::el8, p-cpe:/a:centos:centos:qemu-kvm-block-curl, p-cpe:/a:centos:centos:libcacard-devel, p-cpe:/a:centos:centos:qemu-kvm-docs, p-cpe:/a:redhat:enterprise_linux:qemu-kvm-block-rbd, p-cpe:/a:centos:centos:qemu-kvm, p-cpe:/a:centos:centos:qemu-kvm-ui-spice, p-cpe:/a:redhat:enterprise_linux:qemu-kvm-block-curl, p-cpe:/a:redhat:enterprise_linux:qemu-kvm-ui-opengl, p-cpe:/a:centos:centos:qemu-img-rhev, p-cpe:/a:canonical:ubuntu_linux:qemu, cpe:/o:canonical:ubuntu_linux:14.04:-:lts, p-cpe:/a:redhat:enterprise_linux:qemu-kvm-tools, p-cpe:/a:redhat:enterprise_linux:qemu-kvm-ui-spice, p-cpe:/a:redhat:enterprise_linux:qemu-kvm, p-cpe:/a:centos:centos:qemu-kvm-block-rbd, p-cpe:/a:redhat:enterprise_linux:qemu-kvm-block-ssh, p-cpe:/a:redhat:enterprise_linux:libcacard-tools, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:centos:centos:qemu-kvm-core, p-cpe:/a:centos:centos:qemu-kvm-tools

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

Exploit Available: true

Exploit Ease: Exploits are available

Vulnerability Publication Date: 5/26/2021

Reference Information

CVE: CVE-2021-20196