xen: x86 Incorrect MSR_DEBUGCTL handling lets guests enable BTS (XSA-269)
Published Aug 17, 2018
6.0
MEDIUMCVSS 3.0
EPSS 0.34%
Description
An issue was discovered in Xen through 4.11.x. The DEBUGCTL MSR contains several debugging features, some of which virtualise cleanly, but some do not. In particular, Branch Trace Store is not virtualised by the processor, and software has to be careful to configure it suitably not to lock up the core. As a result, it must only be available to fully trusted guests. Unfortunately, in the case that vPMU is disabled, all value checking was skipped, allowing the guest to choose any MSR_DEBUGCTL setting it likes. A malicious or buggy guest administrator (on Intel x86 HVM or PVH) can lock up the entire host, causing a Denial of Service.
Affected products
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H
AV:L/AC:L/Au:N/C:N/I:N/A:C
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2021–2026- EPSS v1
- EPSS v5
- EPSS v2
- EPSS v3
Percentile over time
- EPSS v1
- EPSS v5
- EPSS v2
- EPSS v3
Table of values (9 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 0.34% (0.00337) | 24.78th | v5 (v2026.06.15) |
| Sep 20, 2026 | 0.34% (0.00337) | 27.26th | v5 (v2026.06.15) |
| Jul 20, 2024 | 0.04% (0.00044) | 12.95th | v3 (v2023.03.01) |
| May 25, 2024 | 0.04% (0.00044) | 12.27th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.04% (0.00044) | 10.26th | v3 (v2023.03.01) |
| Mar 6, 2023 | 0.89% (0.00885) | 27.89th | v2 (v2022.01.01) |
| Feb 4, 2022 | 0.89% (0.00885) | 10.50th | v2 (v2022.01.01) |
| Feb 3, 2022 | 0.78% (0.00777) | 21.50th | v5 (v2026.06.15) |
| Apr 14, 2021 | 0.78% (0.00777) | 0.00th | v1 |
References (6)
- http://xenbits.xen.org/xsa/advisory-269.html x_refsource_MISCVendor Advisory
- https://access.redhat.com/security/cve/CVE-2018-15468 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1610548 Issue Tracking
- https://nvd.nist.gov/vuln/detail/CVE-2018-15468
- https://security.gentoo.org/glsa/201810-06 vendor-advisoryx_refsource_GENTOOThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2018-15468
| Link | Providers | Tags |
|---|---|---|
| http://xenbits.xen.org/xsa/advisory-269.html | x_refsource_MISCVendor Advisory | |
| https://access.redhat.com/security/cve/CVE-2018-15468 | Vendor Advisory | |
| https://bugzilla.redhat.com/show_bug.cgi?id=1610548 | Issue Tracking | |
| https://nvd.nist.gov/vuln/detail/CVE-2018-15468 | ||
| https://security.gentoo.org/glsa/201810-06 | vendor-advisoryx_refsource_GENTOOThird Party Advisory | |
| https://www.cve.org/CVERecord?id=CVE-2018-15468 |
Change history (0)
No recorded changes yet.