Buffer overflow in Xen

CVE-2020-15563

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.

Vulnerability class: Buffer Overflow

EPSS: 0.004 (33.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

References

  • cve@mitre.org (Patch, x_refsource_MISC, Vendor Advisory)
  • cve@mitre.org (mailing-list, x_refsource_MLIST, Mailing List, Third Party Advisory)
  • cve@mitre.org (vendor-advisory, Third Party Advisory, x_refsource_DEBIAN)
  • cve@mitre.org (vendor-advisory, Mailing List, Third Party Advisory, x_refsource_SUSE)
  • cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
  • cve@mitre.org (vendor-advisory, Mailing List, Third Party Advisory, x_refsource_SUSE)
  • cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
  • cve@mitre.org (vendor-advisory, Third Party Advisory, x_refsource_GENTOO)

Frequently asked questions

What is CVE-2020-15563?
CVE-2020-15563 is a medium-severity vulnerability in Xen, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 6.5/10. Published 2020-07-07.
How severe is CVE-2020-15563?
Medium severity. CVSS v3 base score is 6.5 out of 10.