CVE-2015-7835

Description

From CVE.org

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.

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.

Common Vulnerability Scoring System (CVSS) Score Details

Info alert:Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).

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

CVSS v2 Score Breakdown

Red HatNVDcve.org
Base Score7.17.2N/A
Attack VectorNetworkLocalN/A
Access ComplexityHighLowN/A
AuthenticationSingleNoneN/A
Confidentiality ImpactCompleteCompleteN/A
Integrity ImpactCompleteCompleteN/A
Availability ImpactCompleteCompleteN/A

Vector

Red Hat: AV:N/AC:H/Au:S/C:C/I:C/A:C

NVD: AV:L/AC:L/Au:N/C:C/I:C/A:C

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