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Fencer Vulns
medium 4.3

CVE-2018-17204 json

An issue was discovered in Open vSwitch (OvS) 2.7.x through 2.7.6, affecting parse_group_prop_ntr_selection_method in lib/ofp-util.c.

published 2018-09-19 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-8966

cvss
4.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.9%
EPSS 1.9% chance of exploitation in 30 days, percentile 79%
public exploits
0
none known

Summary

An issue was discovered in Open vSwitch (OvS) 2.7.x through 2.7.6, affecting parse_group_prop_ntr_selection_method in lib/ofp-util.c. When decoding a group mod, it validates the group type and command after the whole group mod has been decoded. The OF1.5 decoder, however, tries to use the type and command earlier, when it might still be invalid. This causes an assertion failure (via OVS_NOT_REACHED). ovs-vswitchd does not enable support for OpenFlow 1.5 by default.

Patch / fix

  • openvswitch Debian 14, Debian 13, Debian 12 2.10.0+2018.08.28+git.8ca7c82b7d+ds1-1

debian advisories DEBIAN-CVE-2018-17204

  • openvswitch Ubuntu 16.04 LTS 2.5.5-0ubuntu0.16.04.2
  • openvswitch Ubuntu 18.04 LTS 2.9.2-0ubuntu0.18.04.3

ubuntu advisories UBUNTU-CVE-2018-17204

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

  • openvswitch openstack 13, openstack 10 2.9.0-83.el7fdp.1
  • openvswitch-test openstack 13, openstack 10 2.9.0-83.el7fdp.1
  • python-openvswitch openstack 13, openstack 10 2.9.0-83.el7fdp.1
  • openvswitch-ovn-host openstack 13, openstack 10 2.9.0-83.el7fdp.1
  • openvswitch-ovn-vtep openstack 13, openstack 10 2.9.0-83.el7fdp.1
  • openvswitch-ovn-common openstack 13, openstack 10 2.9.0-83.el7fdp.1
  • openvswitch-ovn-central openstack 13, openstack 10 2.9.0-83.el7fdp.1
  • openvswitch RHEL 7 2.9.0-70.el7fdp.1

red hat advisories RHSA-2019:0081RHSA-2019:0053RHSA-2018:3500RHBA-2018:3683

  • openvswitch SLES for SAP 12 SP3, SLES 12 SP3 2.7.6-3.23.1

suse advisories SUSE-SU-2018:4128-1

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-2018-17204 updated cvss 2.7

openvswitch: Mishandle of group mods in lib/ofp-util.c:parse_group_prop_ntr_selection_method() allows for assertion failure

  • Red Hat OpenStack Platform 8 (Liberty) openvswitch, python-openvswitch Red Hat OpenStack Platform 9 (Mitaka) openvswitch, python-openvswitch Red Hat OpenStack Platform 12 (Pike) openvswitch, openvswitch-test, python-openvswitch, openvswitch-ovn-host, openvswitch-ovn-vtep, openvswitch-ovn-common, +1 more Red Hat Virtualization 4 rhvm-appliance
    affected: no fix planned “Will not fix”
  • Red Hat Fast Datapath for Red Hat Enterprise Linux 7 openvswitch 2.9.0-70.el7fdp.1, openvswitch-test 2.9.0-70.el7fdp.1, python-openvswitch 2.9.0-70.el7fdp.1, openvswitch-ovn-host 2.9.0-70.el7fdp.1, openvswitch-ovn-vtep 2.9.0-70.el7fdp.1, openvswitch-ovn-common 2.9.0-70.el7fdp.1, +1 more
    fixed: vendor fix RHSA-2018:3500
  • Red Hat OpenStack 10.0 Tools for RHEL 7 openvswitch-test 2.9.0-83.el7fdp.1 Red Hat OpenStack Platform 10.0 openvswitch 2.9.0-83.el7fdp.1, python-openvswitch 2.9.0-83.el7fdp.1, openvswitch-ovn-host 2.9.0-83.el7fdp.1, openvswitch-ovn-vtep 2.9.0-83.el7fdp.1, openvswitch-ovn-common 2.9.0-83.el7fdp.1, openvswitch-ovn-central 2.9.0-83.el7fdp.1
    fixed: vendor fix RHSA-2019:0053
  • Red Hat OpenStack Platform 13.0 openvswitch 2.9.0-83.el7fdp.1, openvswitch-test 2.9.0-83.el7fdp.1, python-openvswitch 2.9.0-83.el7fdp.1, openvswitch-ovn-host 2.9.0-83.el7fdp.1, openvswitch-ovn-vtep 2.9.0-83.el7fdp.1, openvswitch-ovn-common 2.9.0-83.el7fdp.1, +1 more
    fixed: vendor fix RHSA-2019:0081
  • Red Hat Virtualization 4 Hypervisor for RHEL 7 redhat-virtualization-host 4.2-20181121.0.el7_6, redhat-virtualization-host-image-update 4.2-20181121.0.el7_6
    fixed: vendor fix RHBA-2018:3683
  • Red Hat Virtualization 4.2 Management Agent for RHEL 7.6 EUS Hosts openvswitch 2.9.0-70.el7fdp.1, python-openvswitch 2.9.0-70.el7fdp.1, openvswitch-ovn-host 2.9.0-70.el7fdp.1, openvswitch-ovn-common 2.9.0-70.el7fdp.1
    fixed: vendor fix RHSA-2018:3500
  • Red Hat RHEL 7-based RHEV-H for RHEV 4 (build requirements) redhat-release-virtualization-host 4.2-7.5.el7, redhat-virtualization-host-image-update-placeholder 4.2-7.5.el7
    fixed: vendor fix RHBA-2018:3683
  • Red Hat Fast Datapath for RHEL 7 openvswitch2.10, openvswitch2.10-test, python-openvswitch2.10, openvswitch2.10-ovn-host, openvswitch2.10-ovn-vtep, openvswitch2.10-ovn-common, +1 more Red Hat Fast Datapath for RHEL 8 openvswitch2.10, openvswitch2.11, openvswitch2.11-test, python3-openvswitch2.11, network-scripts-openvswitch2.11 Red Hat OpenShift Container Platform 3.2 node Red Hat OpenShift Container Platform 3.3 node Red Hat OpenShift Container Platform 3.4 node Red Hat OpenShift Enterprise 3.0 openvswitch, openvswitch-test, python-openvswitch
    +2 more products
    Red Hat OpenShift Enterprise 3.1 node Red Hat OpenStack Platform 14 (Rocky) openvswitch
    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

1.91% chance of exploitation in the next 30 days, higher than 79% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
NVD 2.0 4.0 AV:N/AC:L/Au:S/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.