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Fencer Vulns
medium 5.7

CVE-2019-20485 json

qemu/qemu_driver.c in libvirt before 6.0.0 mishandles the holding of a monitor job during a query to a guest agent, which allows attackers…

published 2020-03-19 6 y ago modified 2026-06-17 4 mo ago also EUVD-2019-11029

cvss
5.7
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 57%
public exploits
0
none known

Summary

qemu/qemu_driver.c in libvirt before 6.0.0 mishandles the holding of a monitor job during a query to a guest agent, which allows attackers to cause a denial of service (API blockage).

Patch / fix

  • redhat libvirt 6.0.0
  • libvirt Debian 14, Debian 13, Debian 12 6.0.0-2

debian advisories DEBIAN-CVE-2019-20485

  • SLOF RHEL 8 20191022-3.git899d9883.module+el8.3.0+6423+e4cb6418
  • hivex RHEL 8 1.3.18-20.module+el8.3.0+6423+e4cb6418
  • netcf RHEL 8 0.2.8-12.module+el8.1.0+4066+0f1aadab
  • libnbd RHEL 8 1.2.2-1.module+el8.3.0+7353+9de0a3cc
  • nbdkit RHEL 8 1.16.2-4.module+el8.3.0+6922+fd575af8
  • libvirt RHEL 8 6.0.0-28.module+el8.3.0+7827+5e65edd7
  • nbdfuse RHEL 8 1.2.2-1.module+el8.3.0+7353+9de0a3cc
  • seabios RHEL 8 1.13.0-2.module+el8.3.0+7353+9de0a3cc

red hat advisories RHSA-2020:4676RHSA-2020:4000RHBA-2020:2017

  • hivex AlmaLinux 8 1.3.18-20.module_el8.3.0+2048+e7a0a3ea
  • netcf AlmaLinux 8 0.2.8-12.module_el8.5.0+2608+72063365
  • netcf AlmaLinux 8 0.2.8-12.module_el8.6.0+2880+7d9e3703
  • netcf AlmaLinux 8 0.2.8-12.module_el8.3.0+2048+e7a0a3ea
  • libnbd AlmaLinux 8 1.2.2-1.module_el8.5.0+2608+72063365
  • libnbd AlmaLinux 8 1.2.2-1.module_el8.3.0+2048+e7a0a3ea
  • nbdkit AlmaLinux 8 1.16.2-4.module_el8.5.0+2608+72063365
  • libvirt AlmaLinux 8 6.0.0-28.module_el8.3.0+2048+e7a0a3ea

almalinux advisories ALSA-2020:4676

  • hivex Rocky Linux 8 1.3.18-20.module+el8.4.0+534+4680a14e
  • netcf Rocky Linux 8 0.2.8-12.module+el8.7.0+1084+97b81f61
  • netcf Rocky Linux 8 0.2.8-12.module+el8.4.0+534+4680a14e
  • netcf Rocky Linux 8 0.2.8-12.module+el8.6.0+847+b490afdd
  • libnbd Rocky Linux 8 1.2.2-1.module+el8.4.0+534+4680a14e
  • nbdkit Rocky Linux 8 1.16.2-4.module+el8.4.0+534+4680a14e
  • seabios Rocky Linux 8 1.13.0-2.module+el8.4.0+534+4680a14e
  • sgabios Rocky Linux 8 1:0.20170427git-3.module+el8.7.0+1084+97b81f61

rocky linux advisories RLSA-2020:4676

  • libvirt Alpine 3.10, Alpine 3.9 5.5.0-r2
  • libvirt Alpine 3.11 5.9.0-r2

alpine advisories ALPINE-CVE-2019-20485

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

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-2019-20485 updated cvss 5.8

libvirt: Potential DoS by holding a monitor job while querying QEMU guest-agent

  • Red Hat Enterprise Linux 5 libvirt Red Hat Enterprise Linux 6 libvirt, libvirt-client, libvirt-python, libvirt-lock-sanlock
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 Advanced Virtualization libvirt, libvirt-nss, libvirt-libs, libvirt-admin, libvirt-client, libvirt-daemon, +22 more
    affected: no fix available
  • Red Hat Advanced Virtualization CodeReady Builder for RHEL 8.2.0 libnbd 1.2.2-1.module+el8.2.0+5644+32ac38d4, netcf 0.2.8-12.module+el8.2.0+4793+b09dd2fb, hivex 1.3.18-20.module+el8.2.0+5588+63a201c3, nbdfuse 1.2.2-1.module+el8.2.0+5644+32ac38d4, libvirt 6.0.0-17.module+el8.2.0+6257+0d066c28, seabios 1.13.0-1.module+el8.2.0+5520+4e5817f3, +45 more Red Hat Advanced Virtualization for RHEL 8.2.0 libnbd 1.2.2-1.module+el8.2.0+5644+32ac38d4, netcf 0.2.8-12.module+el8.2.0+4793+b09dd2fb, hivex 1.3.18-20.module+el8.2.0+5588+63a201c3, nbdfuse 1.2.2-1.module+el8.2.0+5644+32ac38d4, nbdkit 1.16.2-2.module+el8.2.0+5664+dd92f997, libvirt 6.0.0-17.module+el8.2.0+6257+0d066c28, +96 more
    fixed: vendor fix RHBA-2020:2017
  • Red Hat CodeReady Linux Builder (v. 8) libnbd 1.2.2-1.module+el8.3.0+7353+9de0a3cc, netcf 0.2.8-12.module+el8.1.0+4066+0f1aadab, hivex 1.3.18-20.module+el8.3.0+6423+e4cb6418, nbdfuse 1.2.2-1.module+el8.3.0+7353+9de0a3cc, libvirt 6.0.0-28.module+el8.3.0+7827+5e65edd7, seabios 1.13.0-2.module+el8.3.0+7353+9de0a3cc, +39 more Red Hat Enterprise Linux AppStream (v. 8) libnbd 1.2.2-1.module+el8.3.0+7353+9de0a3cc, netcf 0.2.8-12.module+el8.1.0+4066+0f1aadab, hivex 1.3.18-20.module+el8.3.0+6423+e4cb6418, nbdfuse 1.2.2-1.module+el8.3.0+7353+9de0a3cc, nbdkit 1.16.2-4.module+el8.3.0+6922+fd575af8, libvirt 6.0.0-28.module+el8.3.0+7827+5e65edd7, +88 more
    fixed: vendor fix RHSA-2020:4676
  • Red Hat Enterprise Linux Client (v. 7) libvirt 4.5.0-36.el7, libvirt-libs 4.5.0-36.el7, libvirt-client 4.5.0-36.el7, libvirt-daemon 4.5.0-36.el7, libvirt-daemon-kvm 4.5.0-36.el7, libvirt-bash-completion 4.5.0-36.el7, +18 more Red Hat Enterprise Linux Client Optional (v. 7) libvirt-nss 4.5.0-36.el7, libvirt-admin 4.5.0-36.el7, libvirt-daemon-lxc 4.5.0-36.el7, libvirt-login-shell 4.5.0-36.el7, libvirt-lock-sanlock 4.5.0-36.el7 Red Hat Enterprise Linux ComputeNode (v. 7) libvirt 4.5.0-36.el7, libvirt-libs 4.5.0-36.el7, libvirt-client 4.5.0-36.el7, libvirt-bash-completion 4.5.0-36.el7 Red Hat Enterprise Linux ComputeNode Optional (v. 7) libvirt 4.5.0-36.el7, libvirt-nss 4.5.0-36.el7, libvirt-admin 4.5.0-36.el7, libvirt-daemon 4.5.0-36.el7, libvirt-daemon-kvm 4.5.0-36.el7, libvirt-daemon-lxc 4.5.0-36.el7, +20 more Red Hat Enterprise Linux Server (v. 7) libvirt 4.5.0-36.el7, libvirt-libs 4.5.0-36.el7, libvirt-client 4.5.0-36.el7, libvirt-daemon 4.5.0-36.el7, libvirt-daemon-kvm 4.5.0-36.el7, libvirt-bash-completion 4.5.0-36.el7, +18 more Red Hat Enterprise Linux Server Optional (v. 7) libvirt-nss 4.5.0-36.el7, libvirt-admin 4.5.0-36.el7, libvirt-daemon-lxc 4.5.0-36.el7, libvirt-login-shell 4.5.0-36.el7, libvirt-lock-sanlock 4.5.0-36.el7
    +2 more products
    Red Hat Enterprise Linux Workstation (v. 7) libvirt 4.5.0-36.el7, libvirt-libs 4.5.0-36.el7, libvirt-client 4.5.0-36.el7, libvirt-daemon 4.5.0-36.el7, libvirt-daemon-kvm 4.5.0-36.el7, libvirt-bash-completion 4.5.0-36.el7, +18 more Red Hat Enterprise Linux Workstation Optional (v. 7) libvirt-nss 4.5.0-36.el7, libvirt-admin 4.5.0-36.el7, libvirt-daemon-lxc 4.5.0-36.el7, libvirt-login-shell 4.5.0-36.el7, libvirt-lock-sanlock 4.5.0-36.el7
    fixed: vendor fix RHSA-2020:4000

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

0.81% chance of exploitation in the next 30 days, higher than 57% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.7 CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 2.7 AV:A/AC:L/Au:S/C:N/I:N/A:P

Classification

Weakness
  • CWE-20 Improper Input Validation

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.