An issue was discovered in the Linux kernel 5.9.x through 5.11.3, as used with Xen. In some less-common configurations, an x86 PV guest OS user can crash a Dom0 or driver domain via a large amount of I/O activity. The issue relates to misuse of guest physical addresses when a configuration has CONFIG_XEN_UNPOPULATED_ALLOC but not CONFIG_XEN_BALLOON_MEMORY_HOTPLUG.

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2025-414638 advisory.

    An issue was discovered in the Linux kernel 5.9.x through 5.11.3, as used with Xen. In some less-common     configurations, an x86 PV guest OS user can crash a Dom0 or driver domain via a large amount of I/O     activity. The issue relates to misuse of guest physical addresses when a configuration has     CONFIG_XEN_UNPOPULATED_ALLOC but not CONFIG_XEN_BALLOON_MEMORY_HOTPLUG.

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.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - An issue was discovered in the Linux kernel 5.9.x through 5.11.3, as used with Xen. In some less-common     configurations, an x86 PV guest OS user can crash a Dom0 or driver domain via a large amount of I/O     activity. The issue relates to misuse of guest physical addresses when a configuration has     CONFIG_XEN_UNPOPULATED_ALLOC but not CONFIG_XEN_BALLOON_MEMORY_HOTPLUG. (CVE-2021-28039)

Note that Nessus relies on the presence of the package as reported by the vendor.

An update of the linux package has been released.

ID	Name	Product	Family	Type	Severity
267213	Unity Linux 20.1070e Security Update: kernel (UTSA-2025-414638)	Nessus	Unity Linux Local Security Checks	Local	medium
245608	Linux Distros Unpatched Vulnerability : CVE-2021-28039	Nessus	Misc.	Local	medium
148350	Photon OS 4.0: Linux PHSA-2021-4.0-0007	Nessus	PhotonOS Local Security Checks	Local	high

Detections

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CVE-2021-28039

medium

Tenable Plugins

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medium

high