CVE-2023-46839

Guest memory disclosure via incomplete IOMMU assignment

Published Mar 20, 2024 · Updated Nov 4, 2025

Information disclosure in all Xen versions on x86 allows guest OS users to read a previous device owner's memory through PCI passthrough. During device assignment, assign_device continues after an IOMMU context setup failure for a phantom function, leaving function IDs mapped to another domain. Exploitation requires PCI passthrough of a device with phantom functions; Arm systems and Xen hosts without that configuration are unaffected.

CVSS severity5.3
Medium
EPSS probability0.80%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in all Xen versions on x86 allows guest OS users to read a previous device owner's memory through PCI passthrough. During device assignment, assign_device continues after an IOMMU context setup failure for a phantom function, leaving function IDs mapped to another domain. Exploitation requires PCI passthrough of a device with phantom functions; Arm systems and Xen hosts without that configuration are unaffected.

The record

CVE
CVE-2023-46839
Published
Mar 20, 2024
Updated
Nov 4, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 20, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record 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

4.1SUSECVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N
5.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

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 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

No sourced classifications are available.

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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