The Xen Project has released patches to address two vulnerabilities affecting the Xen virtualization software.
An advisory published by the Xen Project on Monday shows that one of the security holes is a leak of uninitialized heap memory related to the RTL8139 network card (CVE-2015-5165).
The vulnerability, caused by the lack of proper input validation in the C+ mode offload emulation, can lead to uninitialized memory from the QEMU machine emulator process’s heap getting leaked to the domain and the network.
The flaw allows a guest to read host-level data relating to itself from the QEMU process, including information on the devices backing the emulated devices, and passwords that the host admin might not want to share with the administrator of the guest system.
“All Xen systems running x86 HVM guests without stubdomains which have been configured with an emulated RTL8139 driver model (which is the default) are vulnerable,” the Xen Project explained in its advisory.