An issue was discovered in Xen through 4.12.x allowing x86 PV guest OS users to gain host OS privileges by leveraging race conditions in pagetable promotion and demotion operations, because of an incomplete fix for CVE-2019-18421. XSA-299 addressed several critical issues in restartable PV type change operations. Despite extensive testing and auditing, some corner cases were missed. A malicious PV guest administrator may be able to escalate their privilege to that of the host. All security-supported versions of Xen are vulnerable. Only x86 systems are affected. Arm systems are not affected. Only x86 PV guests can leverage the vulnerability. x86 HVM and PVH guests cannot leverage the vulnerability. Note that these attacks require very precise timing, which may be difficult to exploit in practice.
CVSS Details
- CVSS 3.1 Base Score: 6.6
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade xen | Feb 11, 2020 | Dec 11, 2019 |
| Debian | — | Upgrade xen | Jan 16, 2020 | Dec 11, 2019 |
| Gentoo Linux | — | Upgrade app-emulation/xen.Upgrade app-emulation/xen-tools. | Mar 27, 2020 | Dec 11, 2019 |
| Redhat_linux | — | No solution exists | Jul 9, 2025 | Dec 11, 2019 |
| Suse | — | Upgrade xen-toolsUpgrade xen-develUpgrade xen-tools-domUUpgrade xen-libsUpgrade xen-doc-htmlUpgrade xen-kmp-paeUpgrade xenUpgrade xen-libs-32bitUpgrade xen-kmp-default | Dec 14, 2019 | Dec 11, 2019 |
| Ubuntu | — | No solution exists | Jun 26, 2025 | Dec 11, 2019 |
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