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CVE-2015-5166

Use-after-free vulnerability in QEMU in Xen 4.5.x and earlier does not completely unplug emulated...

7.2 HighFix available

Use-after-free vulnerability in QEMU in Xen 4.5.x and earlier does not completely unplug emulated block devices, which allows local HVM guest users to gain privileges by unplugging a block device twice.

Exploit likelihood

0.43%Down 0.6 points since Feb 4, 2022
90%50%10%1%

What each source reports

NVD Score used 7.2

Use-after-free vulnerability in QEMU in Xen 4.5.x and earlier does not completely unplug emulated block devices, which allows local HVM guest users to gain privileges by unplugging a block device twice.

Record
CVE-2015-5166
CVSS 2.0
7.2 HighAV:L/AC:L/Au:N/C:C/I:C/A:C
Weakness
CWE-264
Updated
2026-11-02
CVE List No score

Use-after-free vulnerability in QEMU in Xen 4.5.x and earlier does not completely unplug emulated block devices, which allows local HVM guest users to gain privileges by unplugging a block device twice.

Record
CVE-2015-5166
Updated
2026-11-02
EUVDEUVD-2015-5173 No score

Use-after-free vulnerability in QEMU in Xen 4.5.x and earlier does not completely unplug emulated block devices, which allows local HVM guest users to gain privileges by unplugging a block device twice.

Record
EUVD-2015-5173
Updated
2026-11-03
GitHub AdvisoriesGHSA-gpg2-4ppg-g82w No score

Use-after-free vulnerability in QEMU in Xen 4.5.x and earlier does not completely unplug emulated...

Use-after-free vulnerability in QEMU in Xen 4.5.x and earlier does not completely unplug emulated block devices, which allows local HVM guest users to gain privileges by unplugging a block device twice.

Record
GHSA-gpg2-4ppg-g82w
Updated
2026-11-02
OSV No score

Use-after-free vulnerability in QEMU in Xen 4.5.x and earlier does not completely unplug emulated block devices, which allows local HVM guest users to gain privileges by unplugging a block device twice.

Record
CVE-2015-5166
Updated
2026-11-02
OSVDEBIAN-CVE-2015-5166 No score

Use-after-free vulnerability in QEMU in Xen 4.5.x and earlier does not completely unplug emulated block devices, which allows local HVM guest users to gain privileges by unplugging a block device twice.

Record
DEBIAN-CVE-2015-5166
Updated
2026-11-02
Show 5 moreShow less
OSVMGASA-2016-0098 No score

Updated xen packages fix security vulnerabilities

This xen update is based on upstream 4.5.2 maintenance release, and fixes the following security issues:

The vgic_v2_to_sgi function in arch/arm/vgic-v2.c in Xen 4.5.x, when running on ARM hardware with general interrupt controller (GIC) version 2, allows local guest users to cause a denial of service (host crash) by writing an invalid value to the GICD.SGIR register (CVE-2015-0268).

The ARM GIC distributor virtualization in Xen 4.4.x and 4.5.x allows local guests to cause a denial of service by causing a large number messages to be logged (CVE-2015-1563).

The emulation routines for unspecified X86 devices in Xen 3.2.x through 4.5.x does not properly initialize data, which allow local HVM guest users to obtain sensitive information via vectors involving an unsupported access size (CVE-2015-2044).

The HYPERVISOR_xen_version hypercall in Xen 3.2.x through 4.5.x does not properly initialize data structures, which allows local guest users to obtain sensitive information via unspecified vectors (CVE-2015-2045).

Xen 3.3.x through 4.5.x and the Linux kernel through 3.19.1 do not properly restrict access to PCI command registers, which might allow local 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 (CVE-2015-2150).

The x86 emulator in Xen 3.2.x through 4.5.x does not properly ignore segment overrides for instructions with register operands, which allows local guest users to obtain sensitive information, cause a denial of service (memory corruption), or possibly execute arbitrary code via unspecified vectors (CVE-2015-2151).

Xen 4.5.x and earlier enables certain default backends when emulating a VGA device for an x86 HVM guest qemu even when the configuration disables them, which allows local guest users to obtain access to the VGA console by (1) setting the DISPLAY environment variable, when compiled with SDL support, or connecting to the VNC server on (2) ::1 or (3) 127.0.0.1, when not compiled with SDL support (CVE-2015-2152).

Xen 4.3.x, 4.4.x, and 4.5.x, when using toolstack disaggregation, allows remote domains with partial management control to cause a denial of service (host lock) via unspecified domctl operations (CVE-2015-2751).

The XEN_DOMCTL_memory_mapping hypercall in Xen 3.2.x through 4.5.x, when using a PCI passthrough device, is not preemptable, which allows local x86 HVM domain users to cause a denial of service (host CPU consumption) via a crafted request to the device model (qemu-dm) (CVE-2015-2752).

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 (CVE-2015-2756).

Heap-based buffer overflow in the PCNET controller in QEMU allows remote attackers to execute arbitrary code by sending a packet with TXSTATUS_STARTPACKET set and then a crafted packet with TXSTATUS_DEVICEOWNS set (CVE-2015-3209).

Stack-based buffer overflow in the xl command line utility in Xen 4.1.x through 4.5.x allows local guest administrators to gain privileges via a long configuration argument (CVE-2015-3259).

Xen 4.2.x through 4.5.x does not initialize certain fields, which allows certain remote service domains to obtain sensitive information from memory via a (1) XEN_DOMCTL_gettscinfo or (2) XEN_SYSCTL_getdomaininfolist request (CVE-2015-3340).

The Floppy Disk Controller (FDC) in QEMU, as used in Xen 4.5.x and earlier and KVM, allows local guest users to cause a denial of service (out-of-bounds write and guest crash) or possibly execute arbitrary code via the (1) FD_CMD_READ_ID, (2) FD_CMD_DRIVE_SPECIFICATION_COMMAND, or other…

Record
MGASA-2016-0098
Updated
2026-11-02
OSVSUSE-SU-2015:1384-1 No score

security update for xen

This security update of Xen fixes the following issues:

  • bsc#939712 (XSA-140): QEMU leak of uninitialized heap memory in rtl8139 device model (CVE-2015-5165)
  • bsc#939709 (XSA-139): Use after free in QEMU/Xen block unplug protocol (CVE-2015-5166)
Record
SUSE-SU-2015:1384-1
Updated
2026-11-02
OSVSUSE-SU-2015:1404-1 No score

security update for xen

This security update of Xen fixes the following issues:

  • bsc#939712 (XSA-140): QEMU leak of uninitialized heap memory in rtl8139 device model (CVE-2015-5165)
  • bsc#939709 (XSA-139): Use after free in QEMU/Xen block unplug protocol (CVE-2015-5166)
Record
SUSE-SU-2015:1404-1
Updated
2026-11-02
OSVSUSE-SU-2015:1479-1 No score

Security update for xen

xen was updated to fix the following security issues:

  • CVE-2015-5165: QEMU leak of uninitialized heap memory in rtl8139 device model (bsc#939712, XSA-140)
  • CVE-2015-5166: Use after free in QEMU/Xen block unplug protocol (bsc#939709, XSA-139)
  • CVE-2015-2751: Certain domctl operations could have be used to lock up the host (bsc#922709, XSA-127)
  • CVE-2015-3259: xl command line config handling stack overflow (bsc#935634, XSA-137)
  • CVE-2015-4164: DoS through iret hypercall handler (bsc#932996, XSA-136)
  • CVE-2015-5154: Host code execution via IDE subsystem CD-ROM (bsc#938344)
Record
SUSE-SU-2015:1479-1
Updated
2026-11-02
OSVSUSE-SU-2015:1479-2 No score

Security update for xen

xen was updated to fix the following security issues:

  • CVE-2015-5165: QEMU leak of uninitialized heap memory in rtl8139 device model (bsc#939712, XSA-140)
  • CVE-2015-5166: Use after free in QEMU/Xen block unplug protocol (bsc#939709, XSA-139)
  • CVE-2015-2751: Certain domctl operations could have be used to lock up the host (bsc#922709, XSA-127)
  • CVE-2015-3259: xl command line config handling stack overflow (bsc#935634, XSA-137)
  • CVE-2015-4164: DoS through iret hypercall handler (bsc#932996, XSA-136)
  • CVE-2015-5154: Host code execution via IDE subsystem CD-ROM (bsc#938344)
Record
SUSE-SU-2015:1479-2
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
qemu
Debian:12
before 1:2.4+dfsg-1a
1:2.4+dfsg-1a
qemu
Debian:13
before 1:2.4+dfsg-1a
1:2.4+dfsg-1a
qemu
Debian:14
before 1:2.4+dfsg-1a
1:2.4+dfsg-1a
xen
Debian:12
before 4.4.0-1
4.4.0-1
xen
Debian:13
before 4.4.0-1
4.4.0-1
xen
Debian:14
before 4.4.0-1
4.4.0-1
xen
Mageia:5
before 4.5.2-1.5.mga5
4.5.2-1.5.mga5
xen
SUSE:Linux Enterprise Desktop 12
before 4.4.2_10-22.8.1
4.4.2_10-22.8.1
xen
SUSE:Linux Enterprise Software Development Kit 12
before 4.4.2_10-22.8.1
4.4.2_10-22.8.1
xen
SUSE:Linux Enterprise Server 12
before 4.4.2_10-22.8.1
4.4.2_10-22.8.1
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Affected packages
PackageAffectedFixed
xen
SUSE:Linux Enterprise Server for SAP Applications 12
before 4.4.2_10-22.8.1
4.4.2_10-22.8.1
xen
SUSE:Linux Enterprise Software Development Kit 11 SP4
before 4.4.2_12-23.1
4.4.2_12-23.1
xen
SUSE:Linux Enterprise Desktop 11 SP4
before 4.4.2_12-23.1
4.4.2_12-23.1
xen
SUSE:Linux Enterprise Server 11 SP4
before 4.4.2_12-23.1
4.4.2_12-23.1
xen
SUSE:Linux Enterprise Server for SAP Applications 11 SP4
before 4.4.2_12-23.1
4.4.2_12-23.1
xen
SUSE:Linux Enterprise Software Development Kit 11 SP3
before 4.2.5_12-15.1
4.2.5_12-15.1
xen
SUSE:Linux Enterprise Desktop 11 SP3
before 4.2.5_12-15.1
4.2.5_12-15.1
xen
SUSE:Linux Enterprise Server 11 SP3
before 4.2.5_12-15.1
4.2.5_12-15.1
xen
SUSE:Linux Enterprise Server 11 SP3-TERADATA
before 4.2.5_12-15.1
4.2.5_12-15.1
xen
SUSE:Linux Enterprise Server for SAP Applications 11 SP3
before 4.2.5_12-15.1
4.2.5_12-15.1

History

History
RecordedChangedSources
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2015-5166 is a high vulnerability (CVSS 7.2) in Xen, published August 11, 2015. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.43%, the 37th percentile. Fixed in qemu 1:2.4+dfsg-1a.

References

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Left out here: the rest of 1 source description. The JSON record has them.

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