CVE-2016-9921 Denial of service in n/a
A privileged guest user can crash the QEMU host process via a divide-by-zero error in the Cirrus VGA emulator, causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2016-9921?
CVE-2016-9921 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 23 Dec 2016. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Quick emulator (Qemu) built with the Cirrus CLGD 54xx VGA Emulator support is vulnerable to a divide by zero issue. It could occur while copying VGA data when cirrus graphics mode was set to be VGA. A privileged user inside guest could use this flaw to crash the Qemu process instance on the host, resulting in DoS.
Weakness: CWE-369
Which versions are affected by CVE-2016-9921?
It affects 4 products.
Products include Debian Debian Linux, Qemu Qemu, Redhat Openstack, Redhat Virtualization.
How do I fix CVE-2016-9921?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2016-9921 being exploited?
There is no known exploitation of CVE-2016-9921 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as DEBIAN-CVE-2016-9921, GHSA-5wpx-5h74-2wwx, UBUNTU-CVE-2016-9921.