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CVE-2016-9386

20
FAUCET Score

CVE-2016-9386 describes a privilege escalation vulnerability in the x86 emulator of Xen and Citrix XenServer, affecting local HVM guest users. This flaw stems from improper handling of x86 NULL segments, allowing attackers to manipulate base/limit values to gain elevated privileges. With a CVSS v3 score of 7.8 (High), successful exploitation could lead to high impact on confidentiality, integrity, and availability, requiring low attack complexity and user interaction. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
6.0.2CPE matchmatch criteria
cpe:2.3:a:citrix:xenserver:6.0.2:*:*:*:*:*:*:*
6.2.0CPE matchmatch criteria
cpe:2.3:a:citrix:xenserver:6.2.0:*:*:*:*:*:*:*
6.5CPE matchmatch criteria
cpe:2.3:a:citrix:xenserver:6.5:*:*:*:*:*:*:*
7.0CPE matchmatch criteria
cpe:2.3:a:citrix:xenserver:7.0:*:*:*:*:*:*:*
All Versions ImpactedCPE matchmatch criteria
cpe:2.3:o:xen:xen:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

7.8HIGH

CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.8
Impact Score
5.9
CvssVersion
3.0

Exploit Intelligence

EPSS Score
0.45%
Probability of exploitation in next 30 days
EPSS Percentile
36.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0045 is in the 77th percentile among its peer group of 16,994 CVEs.

Social Chatter

No social media mentions found for this CVE.

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.2 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

citrixpatch availablevia nvd_reference
View patch
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: xen

Vendor Advisories (1)

redhatCVE-2016-9386Moderate

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

Nov 22, 2016

References

security.gentoo.org / glsa/201612-56
support.citrix.com / article/CTX218775
PatchThird Party Advisory
securityfocus.com / bid/94471
Third Party AdvisoryVDB Entry
securitytracker.com / id/1037340
Third Party AdvisoryVDB Entry
xenbits.xen.org / xsa/advisory-191.html
PatchVendor Advisory