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Linux Distros Unpatched Vulnerability : CVE-2021-3981

low Nessus Plugin ID 223987

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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 in grub2 was found where its configuration file, known as grub.cfg, is being created with the wrong permission set allowing non privileged users to read its content. This represents a low severity confidentiality issue, as those users can eventually read any encrypted passwords present in grub.cfg.
 This flaw affects grub2 2.06 and previous versions. This issue has been fixed in grub upstream but no version with the fix is currently released. (CVE-2021-3981)

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-2021-3981

https://security-tracker.debian.org/tracker/CVE-2021-3981

https://ubuntu.com/security/CVE-2021-3981

Plugin Details

Severity: Low

ID: 223987

File Name: unpatched_CVE_2021_3981.nasl

Version: 1.5

Type: Local

Agent: unix

Family: Misc.

Published: 3/5/2025

Updated: 7/21/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 1.2

Percentile: 0.01

CVSS v2

Risk Factor: Low

Base Score: 2.1

Temporal Score: 1.8

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

CVSS Score Source: CVE-2021-3981

CVSS v3

Risk Factor: Low

Base Score: 3.3

Temporal Score: 3.1

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

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

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:14.04:-:lts, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:centos:centos:7, cpe:/o:debian:debian_linux:11.0, cpe:/o:redhat:enterprise_linux:7, p-cpe:/a:canonical:ubuntu_linux:grub2-signed, p-cpe:/a:canonical:ubuntu_linux:grub2-unsigned, p-cpe:/a:centos:centos:grub2-common, p-cpe:/a:centos:centos:grub2-efi-aa64-modules, p-cpe:/a:centos:centos:grub2-efi-ia32-cdboot, p-cpe:/a:centos:centos:grub2-efi-ia32-modules, p-cpe:/a:centos:centos:grub2-efi-ia32, p-cpe:/a:centos:centos:grub2-efi-modules, p-cpe:/a:centos:centos:grub2-efi-x64-cdboot, p-cpe:/a:centos:centos:grub2-efi-x64-modules, p-cpe:/a:centos:centos:grub2-efi-x64, p-cpe:/a:centos:centos:grub2-efi, p-cpe:/a:centos:centos:grub2-pc-modules, p-cpe:/a:centos:centos:grub2-pc, p-cpe:/a:centos:centos:grub2-ppc-modules, p-cpe:/a:centos:centos:grub2-ppc64-modules, p-cpe:/a:centos:centos:grub2-ppc64, p-cpe:/a:centos:centos:grub2-ppc64le-modules, p-cpe:/a:centos:centos:grub2-ppc64le, p-cpe:/a:centos:centos:grub2-tools-extra, p-cpe:/a:centos:centos:grub2-tools-minimal, p-cpe:/a:centos:centos:grub2-tools, p-cpe:/a:centos:centos:grub2, p-cpe:/a:debian:debian_linux:grub2, p-cpe:/a:redhat:enterprise_linux:grub2-common, p-cpe:/a:redhat:enterprise_linux:grub2-efi-aa64-modules, p-cpe:/a:redhat:enterprise_linux:grub2-efi-ia32-cdboot, p-cpe:/a:redhat:enterprise_linux:grub2-efi-ia32-modules, p-cpe:/a:redhat:enterprise_linux:grub2-efi-ia32, p-cpe:/a:redhat:enterprise_linux:grub2-efi-modules, p-cpe:/a:redhat:enterprise_linux:grub2-efi-x64-cdboot, p-cpe:/a:redhat:enterprise_linux:grub2-efi-x64-modules, p-cpe:/a:redhat:enterprise_linux:grub2-efi-x64, p-cpe:/a:redhat:enterprise_linux:grub2-efi, p-cpe:/a:redhat:enterprise_linux:grub2-pc-modules, p-cpe:/a:redhat:enterprise_linux:grub2-pc, p-cpe:/a:redhat:enterprise_linux:grub2-ppc-modules, p-cpe:/a:redhat:enterprise_linux:grub2-ppc64-modules, p-cpe:/a:redhat:enterprise_linux:grub2-ppc64, p-cpe:/a:redhat:enterprise_linux:grub2-ppc64le-modules, p-cpe:/a:redhat:enterprise_linux:grub2-ppc64le, p-cpe:/a:redhat:enterprise_linux:grub2-tools-extra, p-cpe:/a:redhat:enterprise_linux:grub2-tools-minimal, p-cpe:/a:redhat:enterprise_linux:grub2-tools, p-cpe:/a:redhat:enterprise_linux:grub2

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: 7/30/2020

Reference Information

CVE: CVE-2021-3981