CVE-2016-4020: Medium severity qemu vulnerability
Qemu emulator built with the Task Priority Register(TPR) optimizations for 32-bit Windows guests, is vulnerable to a information leakage issue. It could occur while accessing Task Priority Register(TPR).
A privileged user/process inside guest could use this issue to leak host memory bytes.
Upstream patch: --------------- -> https://lists.gnu.org/archive/html/qemu-devel/2016-04/msg01118.html
Reference: ---------- -> http://www.openwall.com/lists/oss-security/2016/04/14/3
Other sources
The patchinstruction function in hw/i386/kvmvapic.c in QEMU does not initialize the imm32 variable, which allows local guest OS administrators to obtain sensitive information from host stack memory by accessing the Task Priority Register (TPR).
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2016-4020?
CVE-2016-4020 has a moderate severity rating, as it allows local guest OS administrators to access sensitive information from the host's memory.
How do I fix CVE-2016-4020?
To mitigate CVE-2016-4020, update QEMU to the latest version or apply the patched versions indicated by your distribution.
Is CVE-2016-4020 exploitable remotely?
No, CVE-2016-4020 is not remotely exploitable as the attack requires local access to the guest OS.
Which software versions are affected by CVE-2016-4020?
CVE-2016-4020 affects various versions of QEMU up to and including 2.6.2 and specific versions of Ubuntu and Red Hat OpenStack.
What types of systems are vulnerable to CVE-2016-4020?
Systems running vulnerable versions of QEMU, Ubuntu 12.04, 14.04, 15.10, 16.04, and various Red Hat OpenStack versions are susceptible to CVE-2016-4020.