CVE-2016-9921

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2016-12-23 · updated 2026-06-17
Weakness: CWE-369

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.

Affected products

Debian Linux: 8.0
QEMU: through 2.7.1; 2.8.0-rc0, 2.8.0-rc1, 2.8.0-rc2
OpenStack: 6.0, 7.0, 8, 9, 10, 11
RedHat Virtualization: 4.0

References

http://www.openwall.com/lists/oss-security/2016/12/09/1
http://www.securityfocus.com/bid/94803
https://access.redhat.com/errata/RHSA-2017:2392
https://access.redhat.com/errata/RHSA-2017:2408
https://lists.debian.org/debian-lts-announce/2018/09/msg00007.html
https://security.gentoo.org/glsa/201701-49
http://www.openwall.com/lists/oss-security/2016/12/09/1
http://www.securityfocus.com/bid/94803
https://access.redhat.com/errata/RHSA-2017:2392
https://access.redhat.com/errata/RHSA-2017:2408
https://lists.debian.org/debian-lts-announce/2018/09/msg00007.html
https://security.gentoo.org/glsa/201701-49

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