The compat_iret function in Xen 3.1 through 4.5 iterates the wrong way through a loop, which allows local 32-bit PV guest administrators to cause a denial of service (large loop and system hang) via a hypercall_iret call with EFLAGS.VM set.
The MITRE CVE dictionary describes this issue as:
Find out more about CVE-2015-4164 from the MITRE CVE dictionary dictionary and NIST NVD.
This issue does affect the Xen hypervisor 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 |
Vulmon