CVE-2020-25604: n/a vulnerability

CVE-2020-25604: An issue was discovered in Xen through 4.14.x.

An issue was discovered in Xen through 4.14.x. There is a race condition when migrating timers between x86 HVM vCPUs. When migrating timers of x86 HVM guests between its vCPUs, the locking model used allows for a second vCPU of the same guest (also operating on the timers) to release a lock that it didn't acquire. The most likely effect of the issue is a hang or crash of the hypervisor, i.e., a Denial of Service (DoS). All versions of Xen are affected. Only x86 systems are vulnerable. Arm systems are not vulnerable. Only x86 HVM guests can leverage the vulnerability. x86 PV and PVH cannot leverage the vulnerability. Only guests with more than one vCPU can exploit the vulnerability.

UnknownCVSS not scoredNot KEV-listedUpdatedAug 4, 2024, 15:33 UTC (UTC+00:00)

Security readout for executives and security teams

This flaw can let a qualifying Xen virtual machine crash or hang the host hypervisor. The business impact is service disruption, potentially affecting multiple workloads on the same x86 Xen host. The sources do not show confirmed active exploitation. Exposure is limited to x86 Xen hosts running HVM guests with more than one vCPU. Risk is highest where guests are untrusted or tenant-controlled. Arm systems and x86 PV/PVH guests are not exposed according to the source bundle. Treat as urgent for Xen-based service providers or environments hosting untrusted x86 HVM guests. For single-tenant trusted workloads, prioritize in the normal hypervisor patch cycle, while still recognizing that host denial of service can disrupt many systems. Mitigation focus: Review Xen XSA-336 and distribution advisories for supported updates.; Patch Xen hypervisors through vendor packages or Xen-provided fixes.; Prioritize hosts running untrusted multi-vCPU x86 HVM guests..

Prepared: Jun 5, 2026, 14:11 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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Vulnerability profileCVE Program record

Severity: Unknown
CVSS: Not scored
Known Exploited: No
Published: Sep 23, 2020, 21:18 UTC (UTC+00:00)

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors

0Timeline events

0ADP providers

7Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

CVE List V5 sourceCVE List V5
https://xenbits.xen.org/xsa/advisory-336.htmlCVE reference · x_refsource_MISC
FEDORA-2020-306b84fd07CVE reference · vendor-advisory, x_refsource_FEDORA
FEDORA-2020-f668e579beCVE reference · vendor-advisory, x_refsource_FEDORA
DSA-4769CVE reference · vendor-advisory, x_refsource_DEBIAN
FEDORA-2020-d46fe34349CVE reference · vendor-advisory, x_refsource_FEDORA
GLSA-202011-06CVE reference · vendor-advisory, x_refsource_GENTOO

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus

n/an/an/aListed

Weakness

CWE details

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