CVE-2018-15468
xen - security update
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.
How to fix CVE-2018-15468
To remediate CVE-2018-15468, upgrade the affected package to a fixed version below.
- —upgrade to 4.11.1-r0 or later
- —upgrade to 4.11.1~pre.20180911.5acdd26fdc+dfsg-2 or later
- —upgrade to 4.8.4+xsa273+shim4.10.1+xsa273-1+deb9u10 or later
Is CVE-2018-15468 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- from 0, < 4.11.1-r0
- from 0, < 4.11.1~pre.20180911.5acdd26fdc+dfsg-2
- from 0, < 4.8.4+xsa273+shim4.10.1+xsa273-1+deb9u10
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.0 | CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H |