Improper Privilege Management Affecting xen-libs package, versions <4.10.4_06-3.25.1


Severity

Recommended
0.0
high
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
6.82% (94th percentile)

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  • Snyk IDSNYK-SLES150-XENLIBS-2727111
  • published14 Apr 2022
  • disclosed12 Nov 2019

Introduced: 12 Nov 2019

CVE-2019-18425  (opens in a new tab)
CWE-269  (opens in a new tab)

How to fix?

Upgrade SLES:15.0 xen-libs to version 4.10.4_06-3.25.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream xen-libs package and not the xen-libs package as distributed by SLES. See How to fix? for SLES:15.0 relevant fixed versions and status.

An issue was discovered in Xen through 4.12.x allowing 32-bit PV guest OS users to gain guest OS privileges by installing and using descriptors. There is missing descriptor table limit checking in x86 PV emulation. When emulating certain PV guest operations, descriptor table accesses are performed by the emulating code. Such accesses should respect the guest specified limits, unless otherwise guaranteed to fail in such a case. Without this, emulation of 32-bit guest user mode calls through call gates would allow guest user mode to install and then use descriptors of their choice, as long as the guest kernel did not itself install an LDT. (Most OSes don't install any LDT by default). 32-bit PV guest user mode can elevate its privileges to that of the guest kernel. Xen versions from at least 3.2 onwards are affected. Only 32-bit PV guest user mode can leverage this vulnerability. HVM, PVH, as well as 64-bit PV guests cannot leverage this vulnerability. Arm systems are unaffected.

CVSS Scores

version 3.1