What is CVE-2020-27672?

CVE-2020-27672 is a high-severity vulnerability in Xen, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 7.0/10. Published 2020-10-22.

How severe is CVE-2020-27672?

High severity. CVSS v3 base score is 7.0 out of 10.

Use After Free in Xen

CVE-2020-27672

An issue was discovered in Xen through 4.14.x allowing x86 guest OS users to cause a host OS denial of service, achieve data corruption, or possibly gain privileges by exploiting a race condition that leads to a use-after-free involving 2MiB and 1GiB superpages.

Vulnerability class: Race Condition

Published 2020-10-22 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.0 (High). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.003 (16.3th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 16th percentile — 16.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Xen
Debian Linux — versions 10.0
Fedoraproject Fedora — versions 31
openSUSE Leap — versions 15.1, 15.2

Weakness classification (CWE)

References

xenbits.xen.org/xsa/advisory-345.html (Patch, Vendor Advisory)
xenbits.xen.org/xsa/advisory-345.html (Patch, Vendor Advisory)
lists.opensuse.org/opensuse-security-announce/2020-10/msg00075.html (vendor-advisory, Mailing List, Third Party Advisory)
lists.opensuse.org/opensuse-security-announce/2020-11/msg00025.html (vendor-advisory, Mailing List, Third Party Advisory)
security.gentoo.org/glsa/202011-06 (vendor-advisory, Third Party Advisory)
lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
www.debian.org/security/2020/dsa-4804 (vendor-advisory, Third Party Advisory)
www.openwall.com/lists/oss-security/2021/01/19/7 (mailing-list, Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2020-27672?: CVE-2020-27672 is a high-severity vulnerability in Xen, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 7.0/10. Published 2020-10-22.
How severe is CVE-2020-27672?: High severity. CVSS v3 base score is 7.0 out of 10.