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Fencer Vulns
high 7.8

CVE-2016-9386 json

The x86 emulator in Xen does not properly treat x86 NULL segments as unusable when accessing memory, which might allow local HVM guest user…

published 2017-01-23 9 y ago modified 2026-06-17 4 mo ago also EUVD-2016-10196

cvss
7.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

The x86 emulator in Xen does not properly treat x86 NULL segments as unusable when accessing memory, which might allow local HVM guest users to gain privileges via vectors involving "unexpected" base/limit values.

Patch / fix

  • xen Debian 14, Debian 13, Debian 12 4.8.0-1

debian advisories DEBIAN-CVE-2016-9386

  • xen Ubuntu 14.04 LTS 4.4.2-0ubuntu0.14.04.9
  • xen Ubuntu 16.04 LTS 4.6.0-1ubuntu4.3

ubuntu advisories UBUNTU-CVE-2016-9386

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • xen SLES 11 SP3-LTSS, SLE Point of Sale 11 SP3, OpenStack Cloud 5 +2 more 4.2.5_21-30.1
  • xen SLES for SAP 11 SP4, SLES 11 SP4, SLE Software Development Kit 11 SP4 4.4.4_10-43.5
  • xen SLES for SAP 12 SP1, SLES 12 SP1, SLED 12 SP1 +1 more 4.5.5_02-22.3.1
  • xen SLES for SAP 12 SP2, SLES 12 SP2, SLED 12 SP2 +1 more 4.7.1_02-25.1
  • xen SLES for SAP 12, SLES 12-LTSS 4.4.4_05-22.25.1
  • xen SLES 11 SP2-LTSS 4.1.6_08-32.1

suse advisories SUSE-SU-2016:3273-1SUSE-SU-2016:3174-1SUSE-SU-2016:3156-1SUSE-SU-2016:3083-1SUSE-SU-2016:3067-1SUSE-SU-2016:3044-1

  • xen openSUSE Tumbleweed 4.15.1_01-1.2

opensuse advisories openSUSE-SU-2024:11520-1

  • xen Alpine 3.24, Alpine 3.23, Alpine 3.22 +17 more 4.7.1-r1

alpine advisories ALPINE-CVE-2016-9386

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2016-9386 updated cvss 7.5

xen: x86 null segments not always treated as unusable (XSA-191)

  • Red Hat Enterprise Linux 5 xen
    affected: no fix planned “Will not fix”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 7.8 CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-264 Permissions, Privileges, and Access Controls

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.