CVE-2026-42488

Guest-to-host compromise via stale vCPU page-table reference

Published Jun 18, 2026 · Updated Jun 18, 2026

Memory corruption in Xen 4.15 and later allows guest OS users to escalate privileges, leak data, or interrupt the host. Shadow paging error paths switch page tables without updating the running vCPU reference, leaving mapcache metadata bound to stale mappings. Exploitation requires an x86 host and a 64-bit PV guest in shadow mode, a state used during migration or as an L1TF workaround.

CVSS severity8.1
High
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in Xen 4.15 and later allows guest OS users to escalate privileges, leak data, or interrupt the host. Shadow paging error paths switch page tables without updating the running vCPU reference, leaving mapcache metadata bound to stale mappings. Exploitation requires an x86 host and a 64-bit PV guest in shadow mode, a state used during migration or as an L1TF workaround.

The record

CVE
CVE-2026-42488
Published
Jun 18, 2026
Updated
Jun 18, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-119, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 18, 2026Record 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

8.1CISA-ADPCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

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-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1068Exploitation for Privilege Escalation

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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