Detections
Analytics

Azure Linux 3.0 Security Update: kernel (CVE-2025-21981)

medium Nessus Plugin ID 295203

Synopsis

The remote Azure Linux host is missing one or more security updates.

Description

The version of kernel installed on the remote Azure Linux 3.0 host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the CVE-2025-21981 advisory.

 - In the Linux kernel, the following vulnerability has been resolved: ice: fix memory leak in aRFS after reset Fix aRFS (accelerated Receive Flow Steering) structures memory leak by adding a checker to verify if aRFS memory is already allocated while configuring VSI. aRFS objects are allocated in two cases: - as part of VSI initialization (at probe), and - as part of reset handling However, VSI reconfiguration executed during reset involves memory allocation one more time, without prior releasing already allocated resources. This led to the memory leak with the following signature: [root@os-delivery ~]# cat /sys/kernel/debug/kmemleak unreferenced object 0xff3c1ca7252e6000 (size 8192): comm kworker/0:0, pid 8, jiffies 4296833052 hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace (crc 0):
 [<ffffffff991ec485>] __kmalloc_cache_noprof+0x275/0x340 [<ffffffffc0a6e06a>] ice_init_arfs+0x3a/0xe0 [ice] [<ffffffffc09f1027>] ice_vsi_cfg_def+0x607/0x850 [ice] [<ffffffffc09f244b>] ice_vsi_setup+0x5b/0x130 [ice] [<ffffffffc09c2131>] ice_init+0x1c1/0x460 [ice] [<ffffffffc09c64af>] ice_probe+0x2af/0x520 [ice] [<ffffffff994fbcd3>] local_pci_probe+0x43/0xa0 [<ffffffff98f07103>] work_for_cpu_fn+0x13/0x20 [<ffffffff98f0b6d9>] process_one_work+0x179/0x390 [<ffffffff98f0c1e9>] worker_thread+0x239/0x340 [<ffffffff98f14abc>] kthread+0xcc/0x100 [<ffffffff98e45a6d>] ret_from_fork+0x2d/0x50 [<ffffffff98e083ba>] ret_from_fork_asm+0x1a/0x30 ... (CVE-2025-21981)

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

Solution

Update the affected packages.

See Also

https://nvd.nist.gov/vuln/detail/CVE-2025-21981

Plugin Details

Severity: Medium

ID: 295203

File Name: azure_linux_CVE-2025-21981.nasl

Version: 1.1

Type: local

Published: 1/22/2026

Updated: 1/22/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.4

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

CVSS Score Source: CVE-2025-21981

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 4.8

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

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

Vulnerability Information

CPE: p-cpe:/a:microsoft:azure_linux:kernel-debuginfo, p-cpe:/a:microsoft:azure_linux:kernel-devel, p-cpe:/a:microsoft:azure_linux:kernel-drivers-gpu, p-cpe:/a:microsoft:azure_linux:python3-perf, p-cpe:/a:microsoft:azure_linux:kernel-docs, x-cpe:/o:microsoft:azure_linux, p-cpe:/a:microsoft:azure_linux:kernel, p-cpe:/a:microsoft:azure_linux:kernel-drivers-sound, p-cpe:/a:microsoft:azure_linux:bpftool, p-cpe:/a:microsoft:azure_linux:kernel-drivers-intree-amdgpu, p-cpe:/a:microsoft:azure_linux:kernel-drivers-accessibility, p-cpe:/a:microsoft:azure_linux:kernel-tools

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

Exploit Ease: No known exploits are available

Patch Publication Date: 5/13/2025

Vulnerability Publication Date: 4/1/2025

Reference Information

CVE: CVE-2025-21981