CVE-2015-7835

Impact:
Important
Public Date:
2015-10-29
Bugzilla:
1271971: CVE-2015-7835 xen: Uncontrolled creation of large page mappings by PV guests on x86

The MITRE CVE dictionary describes this issue as:

The mod_l2_entry function in arch/x86/mm.c in Xen 3.4 through 4.6.x does not properly validate level 2 page table entries, which allows local PV guest administrators to gain privileges via a crafted superpage mapping.

Find out more about CVE-2015-7835 from the MITRE CVE dictionary dictionary and NIST NVD.

CVSS v2 metrics

NOTE: The following CVSS v2 metrics and score provided are preliminary and subject to review.

Base Score 7.1
Base Metrics AV:N/AC:H/Au:S/C:C/I:C/A:C
Access Vector Network
Access Complexity High
Authentication Single
Confidentiality Impact Complete
Integrity Impact Complete
Availability Impact Complete

Find out more about Red Hat support for the Common Vulnerability Scoring System (CVSS).

Affected Packages State

Platform Package State
Red Hat Enterprise Linux 5 xen Not affected

Mitigation

Running only HVM guests will avoid this vulnerability. On systems where the guest kernel is controlled by the host rather than guest administrator, running only kernels which do not call these hypercalls will also prevent untrusted guest users from exploiting this issue. However untrusted guest administrators can still trigger it unless further steps are taken to prevent them from loading code into the kernel (e.g. by disabling loadable modules etc) or from using other mechanisms which allow them to run code at kernel privilege.

External References

Last Modified

CVE description copyright © 2017, The MITRE Corporation

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