CVE-2026-12052

USB-stack crash via unchecked control response length

Published Aug 11, 2026 · Updated Aug 11, 2026

Out-of-bounds write in Zephyr RTOS 4.0.0 through 4.4.1 allows physically proximate attackers to crash the USB stack via a CDC NCM request. The usbd_cdc_ncm_cth handler copies an entire 28-byte or 8-byte response into a control buffer sized to the host-supplied wLength without clamping the copy. Exposure requires a firmware image using the device_next USB stack and CDC NCM class to enumerate against a malicious host; the bounded write corrupts adjacent pool memory and interrupts USB service.

CVSS severity5.2
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in Zephyr RTOS 4.0.0 through 4.4.1 allows physically proximate attackers to crash the USB stack via a CDC NCM request. The usbd_cdc_ncm_cth handler copies an entire 28-byte or 8-byte response into a control buffer sized to the host-supplied wLength without clamping the copy. Exposure requires a firmware image using the device_next USB stack and CDC NCM class to enumerate against a malicious host; the bounded write corrupts adjacent pool memory and interrupts USB service.

The record

CVE
CVE-2026-12052
Published
Aug 11, 2026
Updated
Aug 11, 2026
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-787, T1200
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 11, 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=4.0.0 <4.4.2

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=4.0.0 <4.4.2

Published CVSS scores

5.2Zephyr ProjectCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:L/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 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-787Out-of-bounds Write
T1200Hardware Additions

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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