CVE-2026-86566

Guest DoS via receive-descriptor copy-length underflow

Published Oct 14, 2026 · Updated Oct 14, 2026

DPDK lib/vhost copy-length underflow allows guest OS users to interrupt a shared backend via short receive descriptors. The supplied source record identifies vhost enqueue as the locus where runt RX descriptors cause the copy length to underflow. Exploitation requires guest control of those descriptors in an affected backend such as OVS-DPDK; the record does not specify whether interruption is a hang or crash.

CVSS severityUnavailable
Unscored
EPSS probability0.13%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

DPDK lib/vhost copy-length underflow allows guest OS users to interrupt a shared backend via short receive descriptors. The supplied source record identifies vhost enqueue as the locus where runt RX descriptors cause the copy length to underflow. Exploitation requires guest control of those descriptors in an affected backend such as OVS-DPDK; the record does not specify whether interruption is a hang or crash.

The record

CVE
CVE-2026-86566
Published
Oct 14, 2026
Updated
Oct 14, 2026
Vendor
libuser Project
Product
Red Hat OpenShift Container Platform 4
Classifications
T1499.004
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

libuser Project · Red Hat OpenShift Container Platform 4Affected versions are unavailable in this record.
libuser Project · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.
libuser Project · Red Hat OpenStack PlatformAffected versions are unavailable in this record.
libuser Project · Red Hat Enterprise Linux 8Affected versions are unavailable in this record.
libuser Project · Red Hat Enterprise Linux 10Affected versions are unavailable in this record.
libuser Project · Fast Datapath for Red Hat Enterprise LinuxAffected versions are unavailable in this record.

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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