CVE-2022-26356

Host denial of service via dirty-VRAM race

Published Apr 5, 2022 · Updated Aug 3, 2024

Race condition in Xen xen 4.0 and later allows local users to cause host denial of service via concurrent dirty-VRAM tracking and paging log-dirty hypercalls. XEN_DMOP_track_dirty_vram can run while XEN_DOMCTL_SHADOW_OP_OFF tears down log-dirty structures because the operations lack mutually exclusive locking, allowing entries into freed slots and leaking memory. Exploitation requires a domain controlling an x86 HVM guest with hardware-assisted paging, commonly a device-model domain; Arm systems are not vulnerable and PV, PVH, or shadow-mode guests avoid the condition.

CVSS severity5.6
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in Xen xen 4.0 and later allows local users to cause host denial of service via concurrent dirty-VRAM tracking and paging log-dirty hypercalls. XEN_DMOP_track_dirty_vram can run while XEN_DOMCTL_SHADOW_OP_OFF tears down log-dirty structures because the operations lack mutually exclusive locking, allowing entries into freed slots and leaking memory. Exploitation requires a domain controlling an x86 HVM guest with hardware-assisted paging, commonly a device-model domain; Arm systems are not vulnerable and PV, PVH, or shadow-mode guests avoid the condition.

The record

CVE
CVE-2022-26356
Published
Apr 5, 2022
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1499.002
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 5, 2022CVE 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

5.6NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H
4.0NVDAV:L/AC:H/Au:N/C:N/I:N/A:C

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.002Service Exhaustion

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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