Qemu: BlockBackend object use after free issue (XSA-139)
Published Aug 12, 2015
7.2
HIGHCVSS 2.0
EPSS 0.43%
Description
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.
Affected products
No data.
Configuration 1
- 21
- 22
No data.
Red Hat Enterprise Linux 5
kvm
Not affected
Red Hat Enterprise Linux 5
xen
Not affected
Red Hat Enterprise Linux 6
qemu-kvm
Not affected
Red Hat Enterprise Linux 7
qemu-kvm
Not affected
Red Hat Enterprise Linux 7
qemu-kvm-rhev
Not affected
Red Hat Enterprise Linux OpenStack Platform 5 (Icehouse)
qemu-kvm-rhev
Not affected
Red Hat Enterprise Linux OpenStack Platform 6 (Juno)
qemu-kvm-rhev
Not affected
Red Hat Enterprise Linux OpenStack Platform 7 (Kilo)
qemu-kvm-rhev
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 5 | kvm | Not affected | n/a |
| Red Hat Enterprise Linux 5 | xen | Not affected | n/a |
| Red Hat Enterprise Linux 6 | qemu-kvm | Not affected | n/a |
| Red Hat Enterprise Linux 7 | qemu-kvm | Not affected | n/a |
| Red Hat Enterprise Linux 7 | qemu-kvm-rhev | Not affected | n/a |
| Red Hat Enterprise Linux OpenStack Platform 5 (Icehouse) | qemu-kvm-rhev | Not affected | n/a |
| Red Hat Enterprise Linux OpenStack Platform 6 (Juno) | qemu-kvm-rhev | Not affected | n/a |
| Red Hat Enterprise Linux OpenStack Platform 7 (Kilo) | qemu-kvm-rhev | Not affected | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
This issue does not affect the versions of kvm and xen packages as shipped with Red Hat Enterprise Linux 5. This issue does not affect the versions of the qemu-kvm packages as shipped with Red Hat Enterprise Linux 6. This issue does not affect the Red Hat Enterprise Linux 6 based versions of qemu-kvm-rhev packages as shipped with Red Hat Enterprise Virtualization 3. This issue does not affect the versions of the qemu-kvm packages as shipped with Red Hat Enterprise Linux 7. This issue does not affect the Red Hat Enterprise Linux 7 based versions of the qemu-kvm-rhev packages as shipped with Red Hat Enterprise Virtualization 3. This issue does not affect the qemu-kvm-rhev packages as shipped with any currently supported versions of Red Hat Enterprise Linux OpenStack Platform.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
No CVSS v3.0 score for this CVE.
AV:L/AC:L/Au:N/C:C/I:C/A:C
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (10 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 0.43% (0.00426) | 34.55th | v5 (v2026.06.15) |
| Jun 15, 2026 | 0.43% (0.00426) | 33.81th | v5 (v2026.06.15) |
| Mar 17, 2025 | 0.14% (0.00136) | 30.93th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.06% (0.00062) | 28.60th | v3 (v2023.03.01) |
| Jun 13, 2024 | 0.06% (0.00062) | 26.61th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.06% (0.00062) | 24.59th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.03% (0.01034) | 41.69th | v2 (v2022.01.01) |
| Sep 10, 2022 | 1.03% (0.01034) | 39.91th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.03% (0.01034) | 37.91th | v2 (v2022.01.01) |
| Feb 4, 2022 | 1.03% (0.01034) | 20.32th | v2 (v2022.01.01) |
References (10)
- http://lists.fedoraproject.org/pipermail/package-announce/2015-September/165373.html vendor-advisoryx_refsource_FEDORA
- http://lists.fedoraproject.org/pipermail/package-announce/2015-September/167792.html vendor-advisoryx_refsource_FEDORA
- http://lists.fedoraproject.org/pipermail/package-announce/2015-September/167820.html vendor-advisoryx_refsource_FEDORA
- http://www.securityfocus.com/bid/76152 vdb-entryx_refsource_BID
- http://www.securitytracker.com/id/1033175 vdb-entryx_refsource_SECTRACK
- http://xenbits.xen.org/xsa/advisory-139.html x_refsource_CONFIRMPatchVendor Advisory
- https://access.redhat.com/security/cve/CVE-2015-5166 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1248997 Issue Tracking
- https://nvd.nist.gov/vuln/detail/CVE-2015-5166
- https://www.cve.org/CVERecord?id=CVE-2015-5166
| Link | Providers | Tags |
|---|---|---|
| http://lists.fedoraproject.org/pipermail/package-announce/2015-September/165373.html | vendor-advisoryx_refsource_FEDORA | |
| http://lists.fedoraproject.org/pipermail/package-announce/2015-September/167792.html | vendor-advisoryx_refsource_FEDORA | |
| http://lists.fedoraproject.org/pipermail/package-announce/2015-September/167820.html | vendor-advisoryx_refsource_FEDORA | |
| http://www.securityfocus.com/bid/76152 | vdb-entryx_refsource_BID | |
| http://www.securitytracker.com/id/1033175 | vdb-entryx_refsource_SECTRACK | |
| http://xenbits.xen.org/xsa/advisory-139.html | x_refsource_CONFIRMPatchVendor Advisory | |
| https://access.redhat.com/security/cve/CVE-2015-5166 | Vendor Advisory | |
| https://bugzilla.redhat.com/show_bug.cgi?id=1248997 | Issue Tracking | |
| https://nvd.nist.gov/vuln/detail/CVE-2015-5166 | ||
| https://www.cve.org/CVERecord?id=CVE-2015-5166 |
Change history (0)
No recorded changes yet.