CVE-2018-17205 Denial of service in n/a
A logic error in Open vSwitch flow bundle processing causes an assertion failure and crash, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2018-17205?
CVE-2018-17205 is a high-severity denial of service vulnerability in Canonical Ubuntu Linux, published on 19 Sep 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-617
Which versions are affected by CVE-2018-17205?
It affects 3 products.
Products include Canonical Ubuntu Linux, Openvswitch Openvswitch, Redhat Openstack.
How do I fix CVE-2018-17205?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2018-17205 being exploited?
There is no known exploitation of CVE-2018-17205 in the wild and no public exploit code.
Other vulnerabilities in Canonical Ubuntu Linux
Sources
Also known as DEBIAN-CVE-2018-17205, GHSA-vxv4-rrx9-5xfq, UBUNTU-CVE-2018-17205.