Amazon Linux 2023 : grub2-common, grub2-efi-aa64, grub2-efi-aa64-cdboot (ALAS2023-2025-1342)

medium Nessus Plugin ID 282374

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Synopsis

The remote Amazon Linux 2023 host is missing a security update.

Description

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2025-1342 advisory.

A vulnerability has been identified in the GRUB2 bootloader's network module that poses an immediate Denial of Service (DoS) risk. This flaw is a Use-after-Free issue, caused because the net_set_vlan command is not properly unregistered when the network module is unloaded from memory. An attacker who can execute this command can force the system to access memory locations that are no longer valid. Successful exploitation leads directly to system instability, which can result in a complete crash and halt system availability (CVE-2025-54770)

A use-after-free vulnerability has been identified in the GNU GRUB (Grand Unified Bootloader). The flaw occurs because the file-closing process incorrectly retains a memory pointer, leaving an invalid reference to a file system structure. An attacker could exploit this vulnerability to cause grub to crash, leading to a Denial of Service. Possible data integrity or confidentiality compromise is not discarded.
(CVE-2025-54771)

A vulnerability has been identified in the GRUB (Grand Unified Bootloader) component. This flaw occurs because the bootloader mishandles string conversion when reading information from a USB device, allowing an attacker to exploit inconsistent length values. A local attacker can connect a maliciously configured USB device during the boot sequence to trigger this issue. A successful exploitation may lead GRUB to crash, leading to a Denial of Service. Data corruption may be also possible, although given the complexity of the exploit the impact is most likely limited. (CVE-2025-61661)

A Use-After-Free vulnerability has been discovered in GRUB's gettext module. This flaw stems from a programming error where the gettext command remains registered in memory after its module is unloaded. An attacker can exploit this condition by invoking the orphaned command, causing the application to access a memory location that is no longer valid. An attacker could exploit this vulnerability to cause grub to crash, leading to a Denial of Service. Possible data integrity or confidentiality compromise is not discarded. (CVE-2025-61662)

A vulnerability has been identified in the GRUB2 bootloader's normal command that poses an immediate Denial of Service (DoS) risk. This flaw is a Use-after-Free issue, caused because the normal command is not properly unregistered when the module is unloaded. An attacker who can execute this command can force the system to access memory locations that are no longer valid. Successful exploitation leads directly to system instability, which can result in a complete crash and halt system availability. Impact on the data integrity and confidentiality is also not discarded. (CVE-2025-61663)

A vulnerability in the GRUB2 bootloader has been identified in the normal module. This flaw, a memory Use After Free issue, occurs because the normal_exit command is not properly unregistered when its related module is unloaded. An attacker can exploit this condition by invoking the command after the module has been removed, causing the system to improperly access a previously freed memory location. This leads to a system crash or possible impacts in data confidentiality and integrity. (CVE-2025-61664)

Tenable has extracted the preceding description block directly from the tested product security advisory.

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

Solution

Run 'dnf update grub2 --releasever 2023.10.20260105' or or 'dnf update --advisory ALAS2023-2025-1342 --releasever 2023.10.20260105' to update your system.

Plugin Details

Severity: Medium

ID: 282374

File Name: al2023_ALAS2023-2025-1342.nasl

Version: 1.1

Type: local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 1/8/2026

Updated: 1/8/2026

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

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Low

Base Score: 3.7

Temporal Score: 2.7

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

CVSS Score Source: CVE-2025-61664

CVSS v3

Risk Factor: Medium

Base Score: 4.9

Temporal Score: 4.3

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

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

CVSS Score Source: CVE-2025-61662

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:grub2-debuginfo, p-cpe:/a:amazon:linux:grub2-efi-x64-cdboot, p-cpe:/a:amazon:linux:grub2-efi-aa64, p-cpe:/a:amazon:linux:grub2-tools-efi, p-cpe:/a:amazon:linux:grub2-efi-aa64-modules, p-cpe:/a:amazon:linux:grub2-efi-aa64-ec2, p-cpe:/a:amazon:linux:grub2-debugsource, p-cpe:/a:amazon:linux:grub2-emu, p-cpe:/a:amazon:linux:grub2-tools-extra, p-cpe:/a:amazon:linux:grub2-efi-aa64-cdboot, p-cpe:/a:amazon:linux:grub2-efi-x64-modules, p-cpe:/a:amazon:linux:grub2-pc-modules, p-cpe:/a:amazon:linux:grub2-tools-minimal-debuginfo, p-cpe:/a:amazon:linux:grub2-tools-extra-debuginfo, p-cpe:/a:amazon:linux:grub2-efi-x64, p-cpe:/a:amazon:linux:grub2-emu-debuginfo, p-cpe:/a:amazon:linux:grub2-common, p-cpe:/a:amazon:linux:grub2-tools-debuginfo, cpe:/o:amazon:linux:2023, p-cpe:/a:amazon:linux:grub2-pc, p-cpe:/a:amazon:linux:grub2-tools-minimal, p-cpe:/a:amazon:linux:grub2-tools, p-cpe:/a:amazon:linux:grub2-tools-efi-debuginfo, p-cpe:/a:amazon:linux:grub2-efi-x64-ec2, p-cpe:/a:amazon:linux:grub2-emu-modules

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 1/7/2026

Vulnerability Publication Date: 11/18/2025

Reference Information

CVE: CVE-2025-54770, CVE-2025-54771, CVE-2025-61661, CVE-2025-61662, CVE-2025-61663, CVE-2025-61664

Detections

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