Amazon Linux 2 : kernel (ALASKERNEL-5.4-2025-099)

high Nessus Plugin ID 235794

Synopsis

The remote Amazon Linux 2 host is missing a security update.

Description

The version of kernel installed on the remote host is prior to 5.4.156-83.273. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2KERNEL-5.4-2025-099 advisory.

A race condition accessing file object in the Linux kernel OverlayFS subsystem was found in the way users do rename in specific way with OverlayFS. A local user could use this flaw to crash the system.
(CVE-2021-20321)

A flaw was found in the Linux kernel. A memory leak in the ccp-ops crypto driver can allow attackers to cause a denial of service. This vulnerability is similar with the older CVE-2019-18808. The highest threat from this vulnerability is to system availability. (CVE-2021-3744)

A memory leak flaw was found in the Linux kernel's ccp_run_aes_gcm_cmd() function that allows an attacker to cause a denial of service. The vulnerability is similar to the older CVE-2019-18808. The highest threat from this vulnerability is to system availability. (CVE-2021-3764)

An out-of-bounds (OOB) memory write flaw was found in prealloc_elems_and_freelist in kernel/bpf/stackmap.c in the bpf in the Linux kernel. In this flaw, the multiplication to calculate the size could lead to an integer overflow which could allow a local attacker, with a special user privilege, to gain access to out- of-bounds memory leading to a system crash or a leak of internal kernel information. (CVE-2021-41864)

In the Linux kernel, the following vulnerability has been resolved:

binder: make sure fd closes complete (CVE-2021-47360)

In the Linux kernel, the following vulnerability has been resolved:

irqchip/gic-v3-its: Fix potential VPE leak on error (CVE-2021-47373)

In the Linux kernel, the following vulnerability has been resolved:

blktrace: Fix uaf in blk_trace access after removing by sysfs (CVE-2021-47375)

In the Linux kernel, the following vulnerability has been resolved:

bpf: Add oversize check before call kvcalloc() (CVE-2021-47376)

In the Linux kernel, the following vulnerability has been resolved:

blk-cgroup: fix UAF by grabbing blkcg lock before destroying blkg pd (CVE-2021-47379)

In the Linux kernel, the following vulnerability has been resolved:

tty: Fix out-of-bound vmalloc access in imageblit (CVE-2021-47383)

In the Linux kernel, the following vulnerability has been resolved:

hwmon: (w83793) Fix NULL pointer dereference by removing unnecessary structure field (CVE-2021-47384)

In the Linux kernel, the following vulnerability has been resolved:

hwmon: (w83791d) Fix NULL pointer dereference by removing unnecessary structure field (CVE-2021-47386)

In the Linux kernel, the following vulnerability has been resolved:

cpufreq: schedutil: Use kobject release() method to free sugov_tunables (CVE-2021-47387)

In the Linux kernel, the following vulnerability has been resolved:

net: sched: flower: protect fl_walk() with rcu (CVE-2021-47402)

In the Linux kernel, the following vulnerability has been resolved:

HID: betop: fix slab-out-of-bounds Write in betop_probe (CVE-2021-47404)

In the Linux kernel, the following vulnerability has been resolved:

can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv (CVE-2021-47459)

In the Linux kernel, the following vulnerability has been resolved:

audit: fix possible null-pointer dereference in audit_filter_rules (CVE-2021-47464)

In the Linux kernel, the following vulnerability has been resolved:

nvmem: Fix shift-out-of-bound (UBSAN) with byte size cells (CVE-2021-47497)

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 'yum update kernel' to update your system.

Plugin Details

Severity: High

ID: 235794

File Name: al2_ALASKERNEL-5_4-2025-099.nasl

Version: 1.1

Type: local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 5/13/2025

Updated: 5/13/2025

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.6

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

CVSS Score Source: CVE-2021-41864

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 7

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

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

CVSS Score Source: CVE-2021-47459

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:perf, p-cpe:/a:amazon:linux:bpftool, p-cpe:/a:amazon:linux:perf-debuginfo, p-cpe:/a:amazon:linux:kernel-tools-debuginfo, p-cpe:/a:amazon:linux:kernel-debuginfo-common-aarch64, p-cpe:/a:amazon:linux:kernel-tools, p-cpe:/a:amazon:linux:kernel-devel, p-cpe:/a:amazon:linux:python-perf-debuginfo, p-cpe:/a:amazon:linux:kernel, p-cpe:/a:amazon:linux:kernel-debuginfo, p-cpe:/a:amazon:linux:kernel-headers, cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:bpftool-debuginfo, p-cpe:/a:amazon:linux:kernel-tools-devel, p-cpe:/a:amazon:linux:kernel-debuginfo-common-x86_64, p-cpe:/a:amazon:linux:python-perf

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

Exploit Available: true

Exploit Ease: No known exploits are available

Patch Publication Date: 4/16/2025

Vulnerability Publication Date: 7/21/2021

Reference Information

CVE: CVE-2021-20321, CVE-2021-3744, CVE-2021-3764, CVE-2021-41864, CVE-2021-47360, CVE-2021-47373, CVE-2021-47375, CVE-2021-47376, CVE-2021-47379, CVE-2021-47383, CVE-2021-47384, CVE-2021-47386, CVE-2021-47387, CVE-2021-47402, CVE-2021-47404, CVE-2021-47459, CVE-2021-47464, CVE-2021-47497

Detections

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