# 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.

- **Severity:** High 7.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Sep 2018
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-17205, GHSA-vxv4-rrx9-5xfq, UBUNTU-CVE-2018-17205

## 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 (Reachable Assertion)

## Which versions are affected by CVE-2018-17205?

It affects 3 products.


Products: Canonical Ubuntu Linux, Openvswitch Openvswitch, Redhat Openstack.

## How do I fix CVE-2018-17205?

Upgrade to a fixed version.

## 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

- [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild)
- [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-17205 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2018-17205 in the wild and no public exploit code.

Affected product: Canonical Ubuntu Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2018-17205/ (Markdown: https://insights.sbomify.com/CVE-2018-17205/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-17205
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-17205
- OSV: https://osv.dev/vulnerability/CVE-2018-17205

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-17205/
Summaries are generated and may contain mistakes; the official description above is the record.