CVE-2018-17204

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-09-19 · updated 2026-06-17
Weakness: CWE-617

Description

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: 16.04, 18.04
Debian Linux: 9.0
Openvswitch: from 2.7.0 through 2.7.6
OpenStack: 10, 13

References

https://access.redhat.com/errata/RHSA-2018:3500
https://access.redhat.com/errata/RHSA-2019:0053
https://access.redhat.com/errata/RHSA-2019:0081
https://github.com/openvswitch/ovs/commit/4af6da3b275b764b1afe194df6499b33d2bf4cde
https://lists.debian.org/debian-lts-announce/2021/02/msg00032.html
https://usn.ubuntu.com/3873-1/
https://access.redhat.com/errata/RHSA-2018:3500
https://access.redhat.com/errata/RHSA-2019:0053
https://access.redhat.com/errata/RHSA-2019:0081
https://github.com/openvswitch/ovs/commit/4af6da3b275b764b1afe194df6499b33d2bf4cde
https://lists.debian.org/debian-lts-announce/2021/02/msg00032.html
https://usn.ubuntu.com/3873-1/

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