CVE-2021-28039

Domain crash via out-of-range guest addresses

Published Mar 5, 2021 · Updated Aug 3, 2024

Denial of service in Linux kernels 5.9.0 through 5.11.3 allows guest OS users to crash a Xen Dom0 or driver domain via heavy I/O. The kernel maps foreign pages through ZONE_DEVICE guest physical addresses that fall outside the p2m range, so the mapping fails and crashes the domain. Only x86 PV domains with CONFIG_XEN_UNPOPULATED_ALLOC enabled and CONFIG_XEN_BALLOON_MEMORY_HOTPLUG disabled are affected; upstream defaults are not.

CVSS severity6.5
Medium
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Linux kernels 5.9.0 through 5.11.3 allows guest OS users to crash a Xen Dom0 or driver domain via heavy I/O. The kernel maps foreign pages through ZONE_DEVICE guest physical addresses that fall outside the p2m range, so the mapping fails and crashes the domain. Only x86 PV domains with CONFIG_XEN_UNPOPULATED_ALLOC enabled and CONFIG_XEN_BALLOON_MEMORY_HOTPLUG disabled are affected; upstream defaults are not.

The record

CVE
CVE-2021-28039
Published
Mar 5, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-131, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 5, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
2.1NIST NVDAV:L/AC:L/Au:N/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-131Incorrect Calculation of Buffer Size
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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