CVE-2026-10647

Network transmission hang via unchecked TX enqueue failure

Published Jun 29, 2026 · Updated Jun 29, 2026

Deadlock in Zephyr RTOS 4.1.0 through 4.4.0 allows physically proximate attackers to halt network transmission via USB bus suspension. In cdc_ncm_send(), an unchecked usbd_ep_enqueue() failure is followed by an indefinite wait for a completion callback that cannot run. An attached USB host must suspend, reset, disconnect, or disable the active CDC-NCM endpoint while traffic is pending; the shared TX thread then remains blocked until reboot, potentially stalling egress on other interfaces.

CVSS severity5.3
Medium
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deadlock in Zephyr RTOS 4.1.0 through 4.4.0 allows physically proximate attackers to halt network transmission via USB bus suspension. In cdc_ncm_send(), an unchecked usbd_ep_enqueue() failure is followed by an indefinite wait for a completion callback that cannot run. An attached USB host must suspend, reset, disconnect, or disable the active CDC-NCM endpoint while traffic is pending; the shared TX thread then remains blocked until reboot, potentially stalling egress on other interfaces.

The record

CVE
CVE-2026-10647
Published
Jun 29, 2026
Updated
Jun 29, 2026
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-833, CWE-667, T1499.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 29, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 29, 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=4.1.0 <4.5.0

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=4.1.0 <4.5.0

Published CVSS scores

5.3Zephyr ProjectCVSS:3.1/AV:A/AC:H/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.

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

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-833Deadlock
CWE-667Improper Locking
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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