CVE-2021-28039

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2021-03-05 18:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 03:45 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.4% in the next 30 days (EPSS).
• Severity: 6.5 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-03-05 18:15 UTC

Last modified

2026-06-17 03:45 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-131

Record status

Modified

Affected

• Linux Kernel ≤ 5.11.3
• Xen
• Netapp Cloud Backup
• Netapp Solidfire Baseboard Management Controller Firmware

Attack profile CVSS 3.1 · 6.5

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Changed

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-28039.md and follow it. Check whether this project is affected by CVE-2021-28039. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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