SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2020-15563

An issue was discovered in Xen through 4.13.x, allowing x86 HVM guest OS users to cause a hypervisor crash.

MEDIUM 6.5EPSS 0.41%

Does this matter?

Lower severity and a low EPSS score (0.41%). Track it; it rarely justifies an emergency change on its own.

Description

An issue was discovered in Xen through 4.13.x, allowing x86 HVM guest OS users to cause a hypervisor crash. An inverted conditional in x86 HVM guests' dirty video RAM tracking code allows such guests to make Xen de-reference a pointer guaranteed to point at unmapped space. A malicious or buggy HVM guest may cause the hypervisor to crash, resulting in Denial of Service (DoS) affecting the entire host. Xen versions from 4.8 onwards are affected. Xen versions 4.7 and earlier are not affected. Only x86 systems are affected. Arm systems are not affected. Only x86 HVM guests using shadow paging can leverage the vulnerability. In addition, there needs to be an entity actively monitoring a guest's video frame buffer (typically for display purposes) in order for such a guest to be able to leverage the vulnerability. x86 PV guests, as well as x86 HVM guests using hardware assisted paging (HAP), cannot leverage the vulnerability.

CVSS 3.1
6.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
EPSS
0.41% probability · 35th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-119
Affected
xen/xen · debian/debian linux · fedoraproject/fedora · opensuse/leap
Source
cve@mitre.org
EPSS trend
0%3%5%26 October 2026: 0.41%26 October 202626 October 2026

EPSS 0.4% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.