CVE-2026-42492Network attack vector

Host-wide denial of service via premature bitmap teardown

Published Jul 28, 2026 · Updated Jul 28, 2026

Denial of service in Xen allows guest OS users to disrupt Xenstore or crash the hypervisor by binding the VIRQ_DOM_EXC virtual IRQ. The event-channel binding error path tears down the XEN_DOMCTL_get_domain_state bitmap even when that bitmap was never initialized. An unprivileged domain can reach the path, interrupting Xenstore or, less commonly, crashing the hypervisor with host-wide impact.

CVSS severity7.5
High
EPSS probability0.46%
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 Xen allows guest OS users to disrupt Xenstore or crash the hypervisor by binding the VIRQ_DOM_EXC virtual IRQ. The event-channel binding error path tears down the XEN_DOMCTL_get_domain_state bitmap even when that bitmap was never initialized. An unprivileged domain can reach the path, interrupting Xenstore or, less commonly, crashing the hypervisor with host-wide impact.

The record

CVE
CVE-2026-42492
Published
Jul 28, 2026
Updated
Jul 28, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-459, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 28, 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 vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5CISA ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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.

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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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-459Incomplete Cleanup
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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