CVE-2026-10668

Physical USB denial of service via transfer desynchronization

Published Jul 12, 2026 · Updated Jul 12, 2026

Denial of service in Zephyr RTOS 4.4.0 through 4.4.1 allows physically proximate attackers to wedge USB control via canceled transfers. The numaker_hsusbd_ep_trigger function unconditionally arms Control Data IN, so a canceled transfer followed by a new SETUP packet transmits stale data and leaves the endpoint NAK'ing. Direct USB-bus access and an enabled NuMaker HSUSBD controller are required; the USB function stops enumerating or responding until reset or re-plug.

CVSS severity2.4
Low
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Zephyr RTOS 4.4.0 through 4.4.1 allows physically proximate attackers to wedge USB control via canceled transfers. The numaker_hsusbd_ep_trigger function unconditionally arms Control Data IN, so a canceled transfer followed by a new SETUP packet transmits stale data and leaves the endpoint NAK'ing. Direct USB-bus access and an enabled NuMaker HSUSBD controller are required; the USB function stops enumerating or responding until reset or re-plug.

The record

CVE
CVE-2026-10668
Published
Jul 12, 2026
Updated
Jul 12, 2026
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-400, T1499
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 12, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.4.0 <4.5.0

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=4.4.0 <4.5.0

Published CVSS scores

2.4Zephyr ProjectCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
4.6NIST NVDCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499Endpoint Denial of Service

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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