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Mallory
High

Xen x86 APIC error interrupt deadlock in vlapic_error()

IdentifiersCVE-2024-45817CWE-833

CVE-2024-45817 is a denial-of-service vulnerability in Xen’s handling of x86 APIC error interrupts. In the x86 APIC architecture, error conditions are recorded in a status register and the OS may request delivery of an interrupt when a new error occurs. If the APIC error interrupt is configured with an illegal vector, raising that error interrupt itself generates another error. In Xen, this can cause recursive re-entry into vlapic_error(). Although the recursion is bounded because additional interrupts are only generated when new status bits are set, the lock protecting the relevant APIC error state is acquired again during recursive handling, resulting in recursive lock acquisition and deadlock.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

A successful exploit can deadlock Xen and cause the host to crash or become unresponsive. The issue is therefore a host-level denial of service. The provided context specifically states that a malicious administrator of a guest VM may be able to trigger this condition and render the host unavailable.

Mitigation

If you can’t patch tonight, do this now.

Restrict administrative control within guest VMs to trusted users and promptly apply the available Xen/XenServer/Citrix Hypervisor updates. No specific configuration workaround is provided in the supplied content beyond updating affected systems.

Remediation

Patch, then assume compromise.

Apply the vendor-provided updates for affected Xen/XenServer products. The provided context states that Citrix released updates for XenServer 8 and a hotfix for Citrix Hypervisor 8.2 CU1 LTSR to address CVE-2024-45817, and advises customers to update to the latest supported version or install the relevant hotfix per vendor guidance.
PUBLIC EXPLOITS

Exploits

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VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

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VendorProductType
XenXenoperating_system

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What this page doesn’t show

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Exposure mapping

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Threat actor evidence

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Associated malware

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Detection signatures

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Vendor-by-vendor mapping

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Social activity

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