CVE-2016-9386
published 2017-01-23CVE-2016-9386: 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…
PriorityP337high7.8CVSS 3.0
AVLACLPRLUINSUCHIHAH
EPSS
0.45%
36.4th percentile
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.
Affected
16 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| citrix | citrix_adm | — | — |
| citrix | citrix_hypervisor | — | — |
| citrix | citrix_virtual_apps_and_desktops | — | — |
| citrix | endpoint_management | — | — |
| citrix | netscaler_adc | — | — |
| citrix | netscaler_gateway | — | — |
| citrix | xenserver | — | — |
| citrix | xenserver | — | — |
| citrix | xenserver | — | — |
| citrix | xenserver | — | — |
| citrix | xenserver | — | — |
| debian | xen | < xen 4.8.0-1 (bookworm) | xen 4.8.0-1 (bookworm) |
| xen | xen | >= 0 < 4.8.0-1 | 4.8.0-1 |
| xen | xen | >= 0 < 4.8.0-1 | 4.8.0-1 |
| xen | xen | >= 0 < 4.8.0-1 | 4.8.0-1 |
| xen | xen | >= 0 < 4.8.0-1 | 4.8.0-1 |
CVSS provenance
nvdv3.07.8HIGHCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvdv2.04.6MEDIUMAV:L/AC:L/Au:N/C:P/I:P/A:P
osv7.8HIGH
vendor_debian7.8HIGH
vendor_redhat7.8HIGH
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Red Hat
xen: x86 null segments not always treated as unusable (XSA-191)
vendor_redhat·2016-11-22·CVSS 7.8
CVE-2016-9386 [HIGH] xen: x86 null segments not always treated as unusable (XSA-191)
xen: x86 null segments not always treated as unusable (XSA-191)
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.
Package: xen (Red Hat Enterprise Linux 5) - Will not fix
Debian
CVE-2016-9386: xen - The x86 emulator in Xen does not properly treat x86 NULL segments as unusable wh...
vendor_debian·2016·CVSS 7.8
CVE-2016-9386 [HIGH] CVE-2016-9386: xen - The x86 emulator in Xen does not properly treat x86 NULL segments as unusable wh...
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.
Scope: local
bookworm: resolved (fixed in 4.8.0-1)
bullseye: resolved (fixed in 4.8.0-1)
forky: resolved (fixed in 4.8.0-1)
sid: resolved (fixed in 4.8.0-1)
trixie: resolved (fixed in 4.8.0-1)
Citrix
Citrix Security Bulletin CTX218775
vendor_citrix·CVSS 7.9
CVE-2016-9379 [HIGH] Citrix Security Bulletin CTX218775
Citrix Security Bulletin CTX218775
CVE References: CVE-2016-9379, CVE-2016-9380, CVE-2016-9381, CVE-2016-9382, CVE-2016-9383, CVE-2016-9385, CVE-2016-9386, CVE-2025-12101, CVE-2025-62626, CVE-2026-23554, CVE-2026-3055, CVE-2026-4368, CVE-2026-4397
Affected Products: Citrix ADM, Citrix Hypervisor, Citrix Virtual Apps and Desktops, Endpoint Management, NetScaler ADC, NetScaler Gateway, XenServer
GHSA
GHSA-5mmc-9chw-pm3p: 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 p
ghsa_unreviewed·2022-05-17
CVE-2016-9386 [HIGH] GHSA-5mmc-9chw-pm3p: 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 p
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.
OSV
CVE-2016-9386: 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 p
osv·2017-01-23·CVSS 7.8
CVE-2016-9386 [HIGH] CVE-2016-9386: 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 p
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.
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2016-9377 CVE-2016-9378 CVE-2016-9379 CVE-2016-9380 CVE-2016-9381 CVE-2016-9382 CVE-2016-9383 CVE-2016-9384 CVE-2016-9385 CVE-2016-9386 xen: various flaws [fedora-all]
bugzilla·2016-11-22·CVSS 5.5
CVE-2016-9377 [MEDIUM] CVE-2016-9377 CVE-2016-9378 CVE-2016-9379 CVE-2016-9380 CVE-2016-9381 CVE-2016-9382 CVE-2016-9383 CVE-2016-9384 CVE-2016-9385 CVE-2016-9386 xen: various flaws [fedora-all]
CVE-2016-9377 CVE-2016-9378 CVE-2016-9379 CVE-2016-9380 CVE-2016-9381 CVE-2016-9382 CVE-2016-9383 CVE-2016-9384 CVE-2016-9385 CVE-2016-9386 xen: various flaws [fedora-all]
This is an automatically created tracking bug! It was created to ensure
that one or more security vulnerabilities are fixed in affected versions
of Fedora.
For comments that are specific to the vulnerability please use bugs filed
against the "Security Response" product referenced in the "Blocks" field.
For more information see:
http://fedoraproject.org/wiki/Security/TrackingBugs
When submitting as an update, use the fedpkg template provided in the next
comment(s). This will include the bug IDs of this tracking bug as well as
the relevant top-level CVE bugs.
Please also mention the CVE IDs being fixed in the RPM chan
Bugzilla
CVE-2016-9386 xsa191 xen: x86 null segments not always treated as unusable (XSA-191)
bugzilla·2016-11-08·CVSS 7.8
CVE-2016-9386 [HIGH] CVE-2016-9386 xsa191 xen: x86 null segments not always treated as unusable (XSA-191)
CVE-2016-9386 xsa191 xen: x86 null segments not always treated as unusable (XSA-191)
ISSUE DESCRIPTION
The Xen x86 emulator erroneously failed to consider the unusability of
segments when performing memory accesses.
The intended behaviour is as follows: The user data segment (%ds, %es,
%fs and %gs) selectors may be NULL in 32-bit to prevent access. In
64-bit, NULL has a special meaning for user segments, and there is no
way of preventing access. However, in both 32-bit and 64-bit, a NULL
LDT system segment is intended to prevent access.
On Intel hardware, loading a NULL selector zeros the base as well as most
attributes, but sets the limit field to its largest possible value. On AMD
hardware, loading a NULL selector zeros the attributes, leaving the stale base
and limit intact.
Xen ma
http://www.securityfocus.com/bid/94471http://www.securitytracker.com/id/1037340http://xenbits.xen.org/xsa/advisory-191.htmlhttps://security.gentoo.org/glsa/201612-56https://support.citrix.com/article/CTX218775http://www.securityfocus.com/bid/94471http://www.securitytracker.com/id/1037340http://xenbits.xen.org/xsa/advisory-191.htmlhttps://security.gentoo.org/glsa/201612-56https://support.citrix.com/article/CTX218775
2017-01-23
Published