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.
CVSS Details
- CVSS 3.1 Base Score: 4.7
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade xen | Oct 22, 2020 | Sep 23, 2020 |
| Debian | — | Upgrade xen | Oct 5, 2020 | Sep 23, 2020 |
| Gentoo Linux | — | Upgrade app-emulation/xen-tools.Upgrade app-emulation/xen. | Nov 12, 2020 | Sep 23, 2020 |
| Redhat_linux | — | No solution exists | Jul 9, 2025 | Sep 23, 2020 |
| Suse | — | Upgrade xen-doc-htmlUpgrade xen-develUpgrade xen-libs-32bitUpgrade xen-tools-domuUpgrade xenUpgrade xen-kmp-defaultUpgrade xen-toolsUpgrade xen-libsUpgrade xen-tools-xendomains-wait-diskUpgrade xen-kmp-pae | Feb 7, 2021 | Sep 23, 2020 |
| Ubuntu | — | Upgrade xen-hypervisor-4.11-armhfUpgrade xen-utils-commonUpgrade xen-hypervisor-4.11-amd64Upgrade xen-utils-4.11Upgrade xenstore-utilsUpgrade libxengnttab1Upgrade libxenevtchn1Upgrade libxendevicemodel1Upgrade xen-hypervisor-4.11-arm64Upgrade libxenmisc4.11 | Sep 20, 2022 | Sep 23, 2020 |
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