Detections
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Unity Linux 20.1070e Security Update: kernel (UTSA-2025-414577)
high Nessus Plugin ID 267257
Synopsis
The Unity Linux host is missing one or more security updates.Description
The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2025-414577 advisory.A flaw was found in the KVM's AMD code for supporting SVM nested virtualization. The flaw occurs when processing the VMCB (virtual machine control block) provided by the L1 guest to spawn/handle a nested guest (L2). Due to improper validation of the virt_ext field, this issue could allow a malicious L1 to disable both VMLOAD/VMSAVE intercepts and VLS (Virtual VMLOAD/VMSAVE) for the L2 guest. As a result, the L2 guest would be allowed to read/write physical pages of the host, resulting in a crash of the entire system, leak of sensitive data or potential guest-to-host escape.
Tenable has extracted the preceding description block directly from the Unity Linux security advisory.
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 kernel package.See Also
Plugin Details
Severity: High
ID: 267257
File Name: unity_linux_UTSA-2025-414577.nasl
Version: 1.2
Type: local
Published: 10/7/2025
Updated: 10/15/2025
Supported Sensors: Nessus
Risk Information
VPR
Risk Factor: High
Score: 7.3
CVSS v2
Risk Factor: High
Base Score: 7.2
Temporal Score: 5.3
Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C
CVSS Score Source: CVE-2021-3656
CVSS v3
Risk Factor: High
Base Score: 8.8
Temporal Score: 7.7
Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C
Vulnerability Information
Required KB Items: Host/local_checks_enabled, Host/cpu, Host/UOS-Server/release, Host/UOS-Server/rpm-list
Exploit Ease: No known exploits are available
Patch Publication Date: 7/8/2025
Vulnerability Publication Date: 9/4/2021
Reference Information
CVE: CVE-2021-3656