CVE-2015-2756

Gentoo Linux Security Advisory 201504-04

Severity Score

5.5

*CVSS v3

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

QEMU, as used in Xen 3.3.x through 4.5.x, does not properly restrict access to PCI command registers, which might allow local HVM guest users to cause a denial of service (non-maskable interrupt and host crash) by disabling the (1) memory or (2) I/O decoding for a PCI Express device and then accessing the device, which triggers an Unsupported Request (UR) response.

QEMU, utilizado en Xen 3.3.x hasta 4.5.x, no restringe correctamente el acceso a los registros de comandos PCI, lo que podría permitir a usuarios locales invitados de HVM causar una denegación de servicio (non-maskable interrupt (NMI) y caída de anfitrión) mediante la deshabilitación de (1) la memoria o (2) la decodificación I/O para un dispositivo PCI Express y posteriormente accediendo al dispositivo, lo que provoca una respuesta Unsupported Request (UR).

Jason Geffner discovered that QEMU incorrectly handled the virtual floppy driver. This issue is known as VENOM. A malicious guest could use this issue to cause a denial of service, or possibly execute arbitrary code on the host as the user running the QEMU process. In the default installation, when QEMU is used with libvirt, attackers would be isolated by the libvirt AppArmor profile. Daniel P. Berrange discovered that QEMU incorrectly handled VNC websockets. A remote attacker could use this issue to cause QEMU to consume memory, resulting in a denial of service. This issue only affected Ubuntu 14.04 LTS, Ubuntu 14.10 and Ubuntu 15.04. Various other issues were also addressed.

*Credits: N/A

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Local

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

None

Availability

Complete

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2015-03-27 CVE Reserved
2015-04-01 CVE Published
2024-08-06 CVE Updated
2025-05-03 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-264: Permissions, Privileges, and Access Controls

CAPEC

References (13)

URL	Tag	Source
http://lists.nongnu.org/archive/html/qemu-devel/2015-03/msg06179.html	Mailing List
http://support.citrix.com/article/CTX201145	X_refsource_confirm
http://www.securityfocus.com/bid/72577	Vdb Entry
http://www.securitytracker.com/id/1031998	Vdb Entry
https://support.citrix.com/article/CTX206006	X_refsource_confirm

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
http://lists.fedoraproject.org/pipermail/package-announce/2015-April/154574.html	2018-10-30
http://lists.fedoraproject.org/pipermail/package-announce/2015-April/154579.html	2018-10-30
http://lists.fedoraproject.org/pipermail/package-announce/2015-April/155198.html	2018-10-30
http://lists.opensuse.org/opensuse-security-announce/2015-04/msg00014.html	2018-10-30
http://www.debian.org/security/2015/dsa-3259	2018-10-30
http://www.ubuntu.com/usn/USN-2608-1	2018-10-30
http://xenbits.xen.org/xsa/advisory-126.html	2018-10-30
https://security.gentoo.org/glsa/201504-04	2018-10-30

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				7.0 Search vendor "Debian" for product "Debian Linux" and version "7.0"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				8.0 Search vendor "Debian" for product "Debian Linux" and version "8.0"		-		Affected
Xen Search vendor "Xen"		Xen Search vendor "Xen" for product "Xen"				4.3.0 Search vendor "Xen" for product "Xen" and version "4.3.0"		-		Affected
Xen Search vendor "Xen"		Xen Search vendor "Xen" for product "Xen"				4.3.1 Search vendor "Xen" for product "Xen" and version "4.3.1"		-		Affected
Xen Search vendor "Xen"		Xen Search vendor "Xen" for product "Xen"				4.3.2 Search vendor "Xen" for product "Xen" and version "4.3.2"		-		Affected
Xen Search vendor "Xen"		Xen Search vendor "Xen" for product "Xen"				4.4.0 Search vendor "Xen" for product "Xen" and version "4.4.0"		-		Affected
Xen Search vendor "Xen"		Xen Search vendor "Xen" for product "Xen"				4.4.1 Search vendor "Xen" for product "Xen" and version "4.4.1"		-		Affected
Xen Search vendor "Xen"		Xen Search vendor "Xen" for product "Xen"				4.5.0 Search vendor "Xen" for product "Xen" and version "4.5.0"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				20 Search vendor "Fedoraproject" for product "Fedora" and version "20"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				21 Search vendor "Fedoraproject" for product "Fedora" and version "21"		-		Affected
Canonical Search vendor "Canonical"		Ubuntu Linux Search vendor "Canonical" for product "Ubuntu Linux"				12.04 Search vendor "Canonical" for product "Ubuntu Linux" and version "12.04"		lts		Affected
Canonical Search vendor "Canonical"		Ubuntu Linux Search vendor "Canonical" for product "Ubuntu Linux"				14.04 Search vendor "Canonical" for product "Ubuntu Linux" and version "14.04"		lts		Affected
Canonical Search vendor "Canonical"		Ubuntu Linux Search vendor "Canonical" for product "Ubuntu Linux"				14.10 Search vendor "Canonical" for product "Ubuntu Linux" and version "14.10"		-		Affected
Canonical Search vendor "Canonical"		Ubuntu Linux Search vendor "Canonical" for product "Ubuntu Linux"				15.04 Search vendor "Canonical" for product "Ubuntu Linux" and version "15.04"		-		Affected