CVE-2018-17204: Canonical Ubuntu Linux

Medium severity, CVSS 4.3. EPSS: 1.9% chance of exploitation in the next 30 days.

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.

Affected products

• Canonical Ubuntu Linux: version 16.04 only; version 18.04 only
• Debian Debian Linux: version 9.0 only
• Openvswitch Openvswitch: from 2.7.0, up to and including 2.7.6
• Red Hat Openstack: version 10 only; version 13 only

Published 2018-09-19. Last modified 2026-06-17.