Medium
Security advisory
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2018-17204
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 12:26 UTC · Revision 1
Source evidence
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.
osv:CVE-2018-17204
Complete source record
{
"id": "faf618d54c0b654b14758097f234a6bd3399f5d913b8457fde68eb0c9f416fc1",
"url": "https://osv.dev/vulnerability/CVE-2018-17204",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2018-17204",
"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.",
"evidence": "osv:CVE-2018-17204",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2018-17204",
"aliases": [
"CVE-2018-17204"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/openvswitch/ovs",
"type": "GIT",
"events": [
{
"introduced": "c298ef781c2d35d939fe163cbc2f41ea7b1cb8d1"
},
{
"last_affected": "a3830aae25911fef587c08f7301b4665ecc17ae1"
},
{
"fixed": "4af6da3b275b764b1afe194df6499b33d2bf4cde"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:openvswitch:openvswitch:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "2.7.0"
},
{
"last_affected": "2.7.6"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
"fixed": "4af6da3b275b764b1afe194df6499b33d2bf4cde"
}
],
"source": "REFERENCES_COMMIT"
}
]
}
}
],
"versions": [
"v2.7.6",
"v2.7.5",
"v2.7.4",
"v2.7.3",
"v2.7.2",
"v2.7.1",
"v2.7.0"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2018-17204.json",
"vanir_signatures": [
{
"id": "CVE-2018-17204-b51ef21b",
"digest": {
"length": 2184,
"function_hash": "214259102366955435880281220928594186154"
},
"source": "https://github.com/openvswitch/ovs/commit/4af6da3b275b764b1afe194df6499b33d2bf4cde",
"target": {
"file": "lib/ofp-util.c",
"function": "parse_group_prop_ntr_selection_method"
},
"deprecated": false,
"signature_type": "Function",
"signature_version": "v1"
},
{
"id": "CVE-2018-17204-f0ab235d",
"digest": {
"threshold": 0.9,
"line_hashes": [
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"338052315750500283435229193513256384619",
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"324069536227036265479594926544039812313",
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},
"source": "https://github.com/openvswitch/ovs/commit/4af6da3b275b764b1afe194df6499b33d2bf4cde",
"target": {
"file": "lib/ofp-util.c"
},
"deprecated": false,
"signature_type": "Line",
"signature_version": "v1"
}
],
"vanir_signatures_modified": "2026-10-20T13:34:21Z"
}
}
],
"modified": "2026-10-20T13:34:21.450959328Z",
"provider": "osv",
"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://lists.debian.org/debian-lts-announce/2021/02/msg00032.html",
"https://usn.ubuntu.com/3873-1/",
"https://github.com/openvswitch/ovs/commit/4af6da3b275b764b1afe194df6499b33d2bf4cde"
],
"provider_metadata": {
"unresolved_ranges": [
{
"cpes": [
"cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*",
"cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*"
],
"vendor_product": "canonical:ubuntu_linux",
"extracted_events": [
{
"range": [
{
"introduced": "16.04"
},
{
"last_affected": "16.04"
},
{
"introduced": "18.04"
},
{
"last_affected": "18.04"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*"
],
"vendor_product": "debian:debian_linux",
"extracted_events": [
{
"range": [
{
"introduced": "9.0"
},
{
"last_affected": "9.0"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:a:redhat:openstack:10:*:*:*:*:*:*:*",
"cpe:2.3:a:redhat:openstack:13:*:*:*:*:*:*:*"
],
"vendor_product": "redhat:openstack",
"extracted_events": [
{
"range": [
{
"introduced": "10"
},
{
"last_affected": "10"
},
{
"introduced": "13"
},
{
"last_affected": "13"
}
],
"source": "CPE_STRING"
}
]
}
]
}
},
"related_cves": [
{
"value": "CVE-2018-17204",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 387837,
"published_at": "2018-09-19T16:29:00.897+00:00"
}