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Linux Distros Unpatched Vulnerability : CVE-2021-3631

medium Nessus Plugin ID 223959

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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 flaw was found in libvirt while it generates SELinux MCS category pairs for VMs' dynamic labels. This flaw allows one exploited guest to access files labeled for another guest, resulting in the breaking out of sVirt confinement. The highest threat from this vulnerability is to confidentiality and integrity.
 (CVE-2021-3631)

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-2021-3631

https://ubuntu.com/security/CVE-2021-3631

Plugin Details

Severity: Medium

ID: 223959

File Name: unpatched_CVE_2021_3631.nasl

Version: 1.5

Type: local

Agent: unix

Family: Misc.

Published: 3/5/2025

Updated: 9/30/2025

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

Risk Information

VPR

Risk Factor: Medium

Score: 6.0

CVSS v2

Risk Factor: Low

Base Score: 3.3

Temporal Score: 2.6

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

CVSS Score Source: CVE-2021-3631

CVSS v3

Risk Factor: Medium

Base Score: 6.3

Temporal Score: 5.7

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

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

Vulnerability Information

CPE: p-cpe:/a:centos:centos:libvirt-daemon-driver-network, p-cpe:/a:centos:centos:libvirt-daemon-driver-storage-iscsi-direct, cpe:/o:centos:centos:8, p-cpe:/a:redhat:enterprise_linux:libvirt-nss, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-driver-storage, p-cpe:/a:centos:centos:libvirt-wireshark, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-config-nwfilter, p-cpe:/a:centos:centos:libvirt-client, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-driver-storage-disk, p-cpe:/a:redhat:enterprise_linux:libvirt-client, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-driver-qemu, p-cpe:/a:centos:centos:libvirt-daemon-driver-nodedev, p-cpe:/a:centos:centos:libvirt, p-cpe:/a:centos:centos:libvirt-libs, p-cpe:/a:centos:centos:libvirt-daemon-driver-storage, p-cpe:/a:centos:centos:libvirt-daemon-driver-qemu, p-cpe:/a:redhat:enterprise_linux:libvirt, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-driver-nwfilter, p-cpe:/a:centos:centos:libvirt-daemon-driver-storage-disk, p-cpe:/a:centos:centos:libvirt-devel, p-cpe:/a:centos:centos:libvirt-lock-sanlock, p-cpe:/a:centos:centos:libvirt-daemon-driver-storage-iscsi, p-cpe:/a:centos:centos:libvirt-daemon-driver-interface, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-driver-storage-core, cpe:/o:redhat:enterprise_linux:8, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-config-network, p-cpe:/a:centos:centos:libvirt-daemon-driver-storage-gluster, p-cpe:/a:centos:centos:libvirt-daemon-driver-secret, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-driver-storage-iscsi, p-cpe:/a:canonical:ubuntu_linux:libvirt, p-cpe:/a:redhat:enterprise_linux:libvirt-lock-sanlock, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-kvm, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-driver-secret, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-driver-nodedev, p-cpe:/a:centos:centos:libvirt-daemon-driver-storage-rbd, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-driver-storage-mpath, p-cpe:/a:centos:centos:libvirt-daemon-config-network, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-driver-storage-rbd, p-cpe:/a:centos:centos:libvirt-daemon-kvm, p-cpe:/a:centos:centos:libvirt-docs, p-cpe:/a:redhat:enterprise_linux:libvirt-admin, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-driver-storage-scsi, p-cpe:/a:redhat:enterprise_linux:libvirt-wireshark, p-cpe:/a:redhat:enterprise_linux:libvirt-devel, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-driver-interface, p-cpe:/a:centos:centos:libvirt-daemon-driver-storage-scsi, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-driver-storage-logical, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-driver-storage-gluster, p-cpe:/a:redhat:enterprise_linux:libvirt-bash-completion, cpe:/a:redhat:advanced_virtualization:8::el8, p-cpe:/a:centos:centos:libvirt-daemon-config-nwfilter, p-cpe:/a:centos:centos:libvirt-daemon-driver-nwfilter, p-cpe:/a:centos:centos:libvirt-nss, p-cpe:/a:centos:centos:libvirt-bash-completion, p-cpe:/a:centos:centos:libvirt-daemon-driver-storage-mpath, p-cpe:/a:centos:centos:libvirt-admin, p-cpe:/a:centos:centos:libvirt-daemon-driver-storage-logical, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-driver-network, p-cpe:/a:redhat:enterprise_linux:libvirt-libs, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon, p-cpe:/a:redhat:enterprise_linux:libvirt-daemon-driver-storage-iscsi-direct, cpe:/o:canonical:ubuntu_linux:14.04:-:lts, p-cpe:/a:centos:centos:libvirt-daemon, p-cpe:/a:centos:centos:libvirt-daemon-driver-storage-core, p-cpe:/a:redhat:enterprise_linux:libvirt-docs

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: 11/9/2021

Reference Information

CVE: CVE-2021-3631