---
title: "CVE-2018-17204\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2018-17204?format=md
keywords: index, follow
---

# CVE-2018-17204

Publication date 19 September 2018

Last updated 25 August 2025

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**4.3 · Medium**

[Score breakdown](https://ubuntu.com/security/CVE-2018-17204?format=md#impact-score)

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## 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.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2018-17204?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| openvswitch | 18.10 cosmic | Not affected |
| 18.04 LTS bionic | Fixed 2.9.2-0ubuntu0.18.04.3 |
| 16.04 LTS xenial | Fixed 2.5.5-0ubuntu0.16.04.2 |
| 14.04 LTS trusty | Not in release |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)
* [Patch details](https://ubuntu.com/security/CVE-2018-17204?format=md#patch-details)

## Notes

---

### [mdeslaur](https://launchpad.net/~mdeslaur)

openflow 1.5 not enabled by default

### Patch details

For informational purposes only. We recommend not to cherry-pick updates. [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)

| Package | Patch details |
| --- | --- |
| openvswitch | * Upstream:   [9740d81](https://github.com/openvswitch/ovs/commit/9740d81d94888cb158fa99a9366fe2b32b3e4aaa) * Upstream:   [8976ea1](https://github.com/openvswitch/ovs/commit/8976ea1d680ab7a2d726a50e5666aa8fefd24168) * Upstream:   [4af6da3](https://github.com/openvswitch/ovs/commit/4af6da3b275b764b1afe194df6499b33d2bf4cde) * Upstream:   [0e6eb58](https://github.com/openvswitch/ovs/commit/0e6eb58f53d63b79d3a8c6936b0ef72cdd082bdb) * Upstream:   [94b4430](https://github.com/openvswitch/ovs/commit/94b443070fea2a15bc4768c35d59d46892cdc901) |

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

4.3 · Medium

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | Low |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | None |
  | Integrity impact | None |
  | Availability impact | Low |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 4.3 · Medium |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-17204)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2018-17204)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2018-17204)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2018-17204)

### Related Ubuntu Security Notices (USN)

+ [USN-3873-1](https://usn.ubuntu.com/USN-3873-1)
+ Open vSwitch vulnerabilities
+ 30 January 2019

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2018-17204>