CVE-2018-12893

Description

An issue was discovered in Xen through 4.10.x. One of the fixes in XSA-260 added some safety checks to help prevent Xen livelocking with debug exceptions. Unfortunately, due to an oversight, at least one of these safety checks can be triggered by a guest. A malicious PV guest can crash Xen, leading to a Denial of Service. All Xen systems which have applied the XSA-260 fix are vulnerable. Only x86 systems are vulnerable. ARM systems are not vulnerable. Only x86 PV guests can exploit the vulnerability. x86 HVM and PVH guests cannot exploit the vulnerability. An attacker needs to be able to control hardware debugging facilities to exploit the vulnerability, but such permissions are typically available to unprivileged users.

How to fix CVE-2018-12893

To remediate CVE-2018-12893, upgrade the affected package to a fixed version below.

• —upgrade to 4.11.0-r0 or later
• —upgrade to 4.8.3+xsa267+shim4.10.1+xsa267-1+deb9u9 or later

Is CVE-2018-12893 being exploited?

Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• from 0, < 4.11.0-r0
• from 0, < 4.8.3+xsa267+shim4.10.1+xsa267-1+deb9u9

CVSS scores

References (2)

• ADVISORYsecurity.alpinelinux.org/vuln/CVE-2018-12893
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2018-12893