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Vulnerability record · CVE-2016-9637 · published 17 February 2017

CVE-2016-9637: Citrix xenserver permissions and access controls vulnerability

Citrix · Xenserver

The (1) ioport_read and (2) ioport_write functions in Xen, when qemu is used as a device model within Xen, might allow local x86 HVM guest OS administrators to gain qemu process privileges via vectors involving an out-of-range ioport access.

7.5 CVSS 3.0 High EPSS 0.36% · top 72.2% CWE-264 · Permissions and access controls
7.5CVSS 3.0 base score, v2 3.7
0.36%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
14References
17 Jun 2026Last modified by NVD

Description

The (1) ioport_read and (2) ioport_write functions in Xen, when qemu is used as a device model within Xen, might allow local x86 HVM guest OS administrators to gain qemu process privileges via vectors involving an out-of-range ioport access.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://rhn.redhat.com/errata/RHSA-2016-2963.html
http://www.securityfocus.com/bid/94699
http://www.securitytracker.com/id/1037397
http://xenbits.xen.org/xsa/advisory-199.html
https://lists.debian.org/debian-lts-announce/2018/02/msg00005.html
https://security.gentoo.org/glsa/201612-56
https://support.citrix.com/article/CTX219136
http://rhn.redhat.com/errata/RHSA-2016-2963.html
http://www.securityfocus.com/bid/94699
http://www.securitytracker.com/id/1037397
http://xenbits.xen.org/xsa/advisory-199.html
https://lists.debian.org/debian-lts-announce/2018/02/msg00005.html
https://security.gentoo.org/glsa/201612-56
https://support.citrix.com/article/CTX219136

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2014-4947Citrix xenserver memory buffer overflow vulnerabilityBuffer overflow in the HVM graphics console support in Citrix XenServer 6.2 Service Pack 1 and earlier has unspecified impact and attack vectors.EPSS 5.4%9.9CVE-2016-9603Qemu heap-based buffer overflow vulnerabilityA heap buffer overflow flaw was found in QEMU's Cirrus CLGD 54xx VGA emulator's VNC display driver support before 2.9; the issue could occur when a V…EPSS 4.4%9.9CVE-2017-2620Qemu out-of-bounds write vulnerabilityQuick emulator (QEMU) before 2.8 built with the Cirrus CLGD 54xx VGA Emulator support is vulnerable to an out-of-bounds access issue. The issue could…EPSS 3.6%9.8CVE-2018-14007Citrix XenServer directory traversal flawCitrix XenServer 7.1 and newer contains a directory traversal vulnerability (CWE-22) that lets a remote, unauthenticated attacker reach files outside…EPSS 56%analysed9.8CVE-2015-7705Ntp improper input validation vulnerabilityThe rate limiting feature in NTP 4.x before 4.2.8p4 and 4.3.x before 4.3.77 allows remote attackers to have unspecified impact via a large number of …EPSS 12%9.8CVE-2016-5302Citrix xenserver improper access control vulnerabilityCitrix XenServer 7.0 before Hotfix XS70E003, when a deployment has been upgraded from an earlier release, might allow remote attackers on the managem…EPSS 2.6%9.1CVE-2017-2615Qemu out-of-bounds write vulnerabilityQuick emulator (QEMU) built with the Cirrus CLGD 54xx VGA emulator support is vulnerable to an out-of-bounds access issue. It could occur while copyi…EPSS 3.6%8.8CVE-2017-12134Xen vulnerabilityThe xen_biovec_phys_mergeable function in drivers/xen/biomerge.c in Xen might allow local OS guest users to corrupt block device data streams and con…EPSS 0.50%

Source: NIST National Vulnerability Database (record CVE-2016-9637), CISA KEV, FIRST EPSS (scores of 2026-09-29). This page is refreshed as NVD updates the record.