QEMU, as used in Xen 3.3.x through 4.5.x, does not properly restrict access to PCI command registers, which might allow local HVM guest users to cause a denial of service (non-maskable interrupt and host crash) by disabling the (1) memory or (2) I/O decoding for a PCI Express device and then accessing the device, which triggers an Unsupported Request (UR) response.
The MITRE CVE dictionary describes this issue as:
Find out more about CVE-2015-2756 from the MITRE CVE dictionary dictionary and NIST NVD.
This issue dos affect the xen packages as shipped with Red Hat Enterprise Linux 5.
Red Hat Enterprise Linux 5 is now in Production 3 Phase of the support and maintenance life cycle. This has been rated as having Moderate security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.
NOTE: The following CVSS v2 metrics and score provided are preliminary and subject to review.
Base Score | 4.3 |
---|---|
Base Metrics | AV:A/AC:H/Au:S/C:N/I:N/A:C |
Access Vector | Adjacent Network |
Access Complexity | High |
Authentication | Single |
Confidentiality Impact | None |
Integrity Impact | None |
Availability Impact | Complete |
Find out more about Red Hat support for the Common Vulnerability Scoring System (CVSS).
Platform | Package | State |
---|---|---|
Red Hat Enterprise Linux 5 | xen | Will not fix |