SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2018-17205

The assertion failure causes an OvS crash.

HIGH 7.5EPSS 2.53%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (2.53%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

An issue was discovered in Open vSwitch (OvS) 2.7.x through 2.7.6, affecting ofproto_rule_insert__ in ofproto/ofproto.c. During bundle commit, flows that are added in a bundle are applied to ofproto in order. If a flow cannot be added (e.g., the flow action is a go-to for a group id that does not exist), OvS tries to revert back all previous flows that were successfully applied from the same bundle. This is possible since OvS maintains list of old flows that were replaced by flows from the bundle. While reinserting old flows, OvS has an assertion failure due to a check on rule state != RULE_INITIALIZED. This would work for new flows, but for an old flow the rule state is RULE_REMOVED. The assertion failure causes an OvS crash.

CVSS 3.0
7.5 HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
2.53% probability · 85th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-617
Affected
openvswitch/openvswitch · redhat/openstack · canonical/ubuntu linux
Source
cve@mitre.org
EPSS trend
0%3%5%27 October 2026: 2.53%27 October 202627 October 2026

EPSS 2.5% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.