CVE-2015-5166
Qemu: BlockBackend object use after free issue (XSA-139)
Severity
ModerateRed Hat Product Security
CVSS 2.0
Review impact separately from score.
Published · August 3, 2015
Updated · November 21, 2025
Description
A flaw has been found in the QEMU emulator built with IDE Emulation PCI PIIX3/4 support; the emulator is vulnerable to a use-after-free flaw, while writing data to an I/O port inside a guest. This issue is specific to the Xen platform. A privileged(CAP_SYS_RAWIO) guest user on the Xen platform could use this flaw to crash the QEMU instance or attempt to make a guest escape to QEMU-process privileges.
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.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 2.0 · 2.9AV:A/AC:M/Au:N/C:N/I:N/A:P
CWE-416 · Use After Free