Vulnerability in Xen
CVE-2021-3308
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (33.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 33rd percentile — 33.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: -0.000
Affected products
- Xen — versions 4.12.3, 4.12.4
- Fedoraproject Fedora — versions 32
References
- xenbits.xen.org/xsa/advisory-360.html (Patch, Vendor Advisory)
- www.openwall.com/lists/oss-security/2021/01/26/4 (mailing-list, Patch, Mailing List, Third Party Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- security.gentoo.org/glsa/202107-30 (vendor-advisory, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-3308?
- CVE-2021-3308 is a medium-severity vulnerability in Xen. CVSS score: 5.5/10. Published 2021-01-26.
- How severe is CVE-2021-3308?
- Medium severity. CVSS v3 base score is 5.5 out of 10.