How severe is CVE-2016-9921?

CVE-2016-9921 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2016-9921 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-9921?

CVE-2016-9921 primarily affects Redhat Openstack. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2016-9921?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2016-9921 published?

CVE-2016-9921 was published on 2016-12-23 and last updated on 2026-06-17.

CVE-2016-9921

CVE-2016-9921 is a medium-severity vulnerability in Redhat Openstack with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-369.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 2.1
EPSS exploit prediction: 0% (31st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-369
Affected product: Redhat Openstack
Published: 2016-12-23
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2016-9921?: 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.
How severe is CVE-2016-9921?: CVE-2016-9921 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2016-9921 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-9921?: CVE-2016-9921 primarily affects Redhat Openstack. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2016-9921?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2016-9921 published?: CVE-2016-9921 was published on 2016-12-23 and last updated on 2026-06-17.

References

Affected products (12)

cpe:2.3:a:qemu:qemu:*:*:*:*:*:*:*:*
cpe:2.3:a:qemu:qemu:2.8.0:rc0:*:*:*:*:*:*
cpe:2.3:a:qemu:qemu:2.8.0:rc1:*:*:*:*:*:*
cpe:2.3:a:qemu:qemu:2.8.0:rc2:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:a:redhat:openstack:6.0:*:*:*:*:*:*:*
cpe:2.3:a:redhat:openstack:7.0:*:*:*:*:*:*:*
cpe:2.3:a:redhat:openstack:8:*:*:*:*:*:*:*
cpe:2.3:a:redhat:openstack:9:*:*:*:*:*:*:*
cpe:2.3:a:redhat:openstack:10:*:*:*:*:*:*:*
cpe:2.3:a:redhat:openstack:11:*:*:*:*:*:*:*
cpe:2.3:a:redhat:virtualization:4.0:*:*:*:*:*:*:*

More vulnerabilities in Redhat Openstack

CVE-2015-1842 — Critical (CVSS 10.0): The puppet manifests in the Red Hat openstack-puppet-modules package before 2014.2.13-2 uses a default password of…
CVE-2017-2637 — Critical (CVSS 9.9): A design flaw issue was found in the Red Hat OpenStack Platform director use of TripleO to enable libvirtd based…
CVE-2015-5741 — Critical (CVSS 9.8): The net/http library in net/http/transfer.go in Go before 1.4.3 does not properly parse HTTP headers, which allows…
CVE-2013-2167 — Critical (CVSS 9.8): python-keystoneclient version 0.2.3 to 0.2.5 has middleware memcache signing bypass
CVE-2013-2166 — Critical (CVSS 9.8): python-keystoneclient version 0.2.3 to 0.2.5 has middleware memcache encryption bypass
CVE-2018-17963 — Critical (CVSS 9.8): qemu_deliver_packet_iov in net/net.c in Qemu accepts packet sizes greater than INT_MAX, which allows attackers to cause…

All CVEs affecting Redhat Openstack →

Other CWE-369 (Divide By Zero) vulnerabilities

CVE-2021-32494 — Critical (CVSS 10.0): Radare2 has a division by zero vulnerability in Mach-O parser's rebase_buffer function. This allow attackers to create…
CVE-2017-11720 — Critical (CVSS 9.8): There is a division-by-zero vulnerability in LAME 3.99.5, caused by a malformed input file.
CVE-2020-20892 — High (CVSS 8.8): An issue was discovered in function filter_frame in libavfilter/vf_lenscorrection.c in Ffmpeg 4.2.1, allows attackers…
CVE-2025-4637 — High (CVSS 8.7): Divide By Zero vulnerability in davisking dlib allows remote attackers to cause a denial of service via a crafted…
CVE-2026-37232 — High (CVSS 8.6): An issue was discovered in OpenAirInterface5G 2.4.0 (nr-softmodem) in the E2SM-KPM RAN Function's PRB utilization…
CVE-2024-26945 — High (CVSS 8.4): In the Linux kernel, the following vulnerability has been resolved: crypto: iaa - Fix nr_cpus < nr_iaa case If…

Browse all CWE-369 (Divide By Zero) vulnerabilities →