An issue was discovered in Xen through 4.12.x allowing x86 HVM/PVH guest OS users to cause a denial of service (guest OS crash) because VMX VMEntry checks mishandle a certain case. Please see XSA-260 for background on the MovSS shadow. Please see XSA-156 for background on the need for #DB interception. The VMX VMEntry checks do not like the exact combination of state which occurs when #DB in intercepted, Single Stepping is active, and blocked by STI/MovSS is active, despite this being a legitimate state to be in. The resulting VMEntry failure is fatal to the guest. HVM/PVH guest userspace code may be able to crash the guest, resulting in a guest Denial of Service. All versions of Xen are affected. Only systems supporting VMX hardware virtual extensions (Intel, Cyrix, or Zhaoxin CPUs) are affected. Arm and AMD systems are unaffected. Only HVM/PVH guests are affected. PV guests cannot leverage the vulnerability.
This vulnerability carries a HIGH severity rating with a CVSS v3.1 score of 7.5, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts and availability (service disruption) for affected systems. Impacting 4 products from xen, from fedoraproject, from opensuse and 1 other, organizations running these solutions should prioritize assessment and patching.
First disclosed in 2019, this vulnerability was reported during a period defined by widespread IoT adoption challenges, mobile security concerns, and the emergence of advanced persistent threat (APT) techniques. Contemporary mitigation strategies focused on secure development practices and third-party component vetting.
2019-12-11T18:16:19.600
2024-11-21T04:34:59.737
Modified
CVSSv3.1: 7.5 (HIGH)
AV:N/AC:L/Au:N/C:N/I:N/A:P
10.0
2.9
| Type | Vendor | Product | Version/Range | Vulnerable? |
|---|---|---|---|---|
| Operating System | xen | xen | ≤ 4.12.1 | Yes |
| Operating System | fedoraproject | fedora | 30 | Yes |
| Operating System | fedoraproject | fedora | 31 | Yes |
| Operating System | opensuse | leap | 15.1 | Yes |
| Operating System | debian | debian_linux | 9.0 | Yes |
| Operating System | debian | debian_linux | 10.0 | Yes |
SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For xen's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.