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Fencer Vulns
medium 4.4

CVE-2016-6833 json

Use-after-free vulnerability in the vmxnet3_io_bar0_write function in hw/net/vmxnet3.c in QEMU (aka Quick Emulator) allows local guest OS a…

published 2016-12-10 9 y ago modified 2026-06-17 4 mo ago also EUVD-2016-7718

cvss
4.4
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 33%
public exploits
0
none known

Summary

Use-after-free vulnerability in the vmxnet3_io_bar0_write function in hw/net/vmxnet3.c in QEMU (aka Quick Emulator) allows local guest OS administrators to cause a denial of service (QEMU instance crash) by leveraging failure to check if the device is active.

Patch / fix

  • qemu Debian 14, Debian 13, Debian 12 1:2.6+dfsg-3.1

debian advisories DEBIAN-CVE-2016-6833

  • qemu Ubuntu 14.04 LTS 2.0.0+dfsg-2ubuntu1.30
  • qemu Ubuntu 16.04 LTS 1:2.5+dfsg-5ubuntu10.6

ubuntu advisories UBUNTU-CVE-2016-6833

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • qemu SLES for SAP 12 SP1, SLES 12 SP1, SLED 12 SP1 2.3.1-21.1
  • xen SLES for SAP 11 SP4, SLES 11 SP4, SLE Software Development Kit 11 SP4 4.4.4_08-40.2
  • xen SLES for SAP 12 SP1, SLES 12 SP1, SLED 12 SP1 +1 more 4.5.3_10-20.1
  • qemu SLES for SAP 12, SLES 12-LTSS 2.0.2-48.22.1
  • xen SLES for SAP 12, SLES 12-LTSS 4.4.4_04-22.22.2

suse advisories SUSE-SU-2016:2781-1SUSE-SU-2016:2589-1SUSE-SU-2016:2533-1SUSE-SU-2016:2507-1SUSE-SU-2016:2473-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2016-6833 updated cvss 3.5

Qemu: net: vmxnet3: use-after-free while writing to device

  • Red Hat Enterprise Linux 5 kvm, xen Red Hat Enterprise Linux 6 qemu-img, qemu-kvm, qemu-kvm-tools, qemu-guest-agent, qemu-guest-agent-win32 Red Hat Enterprise Linux 7 qemu-img, qemu-kvm, libcacard, qemu-kvm-rhev, qemu-kvm-tools, libcacard-tools, +2 more Red Hat Enterprise Linux OpenStack Platform 5 (Icehouse) qemu-kvm-rhev Red Hat Enterprise Linux OpenStack Platform 6 (Juno) qemu-kvm-rhev Red Hat Enterprise Linux OpenStack Platform 7 (Kilo) qemu-img-rhev, qemu-kvm-rhev, libcacard-rhev, qemu-kvm-tools-rhev, libcacard-devel-rhev, libcacard-tools-rhev, +1 more
    +3 more products
    Red Hat OpenStack Platform 8 (Liberty) qemu-img-rhev, qemu-kvm-rhev, libcacard-rhev, qemu-kvm-tools-rhev, libcacard-devel-rhev, libcacard-tools-rhev, +1 more Red Hat OpenStack Platform 9 (Mitaka) qemu-img-rhev, qemu-kvm-rhev, libcacard-rhev, qemu-kvm-tools-rhev, libcacard-devel-rhev, libcacard-tools-rhev, +1 more Red Hat OpenStack Platform 10 (Newton) qemu-img-rhev, qemu-kvm-rhev, qemu-kvm-tools-rhev, qemu-kvm-common-rhev
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 4.4 CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 2.1 AV:L/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.