CVE-2021-3308

Description

An issue was discovered in Xen 4.12.3 through 4.12.4 and 4.13.1 through 4.14.x. An x86 HVM guest with PCI pass through devices can force the allocation of all IDT vectors on the system by rebooting itself with MSI or MSI-X capabilities enabled and entries setup. Such reboots will leak any vectors used by the MSI(-X) entries that the guest might had enabled, and hence will lead to vector exhaustion on the system, not allowing further PCI pass through devices to work properly. HVM guests with PCI pass through devices can mount a Denial of Service (DoS) attack affecting the pass through of PCI devices to other guests or the hardware domain. In the latter case, this would affect the entire host.

How to fix CVE-2021-3308

To remediate CVE-2021-3308, upgrade the affected package to a fixed version below.

• —upgrade to 4.13.2-r4 or later
• —upgrade to 4.14.1+11-gb0b734a8b3-1 or later

Is CVE-2021-3308 being exploited?

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

Affected packages (2)

• from 0, < 4.13.2-r4
• from 0, < 4.14.1+11-gb0b734a8b3-1

CVSS scores

References (2)

• ADVISORYsecurity.alpinelinux.org/vuln/CVE-2021-3308
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2021-3308