CVE-2026-15923

Permanent service hang via zero SDIO block size

Published Sep 14, 2026 · Updated Sep 14, 2026

Denial of service in Zephyr RTOS 3.6.0 through 4.4.1 allows physically proximate attackers to hang SDIO-dependent services. The byte-I/O loop in sdio_io_rw_extended_helper() uses an unvalidated card-supplied maximum block size as its step, so zero leaves the remaining length unchanged while the card mutex stays locked. Exploitation requires a removable SDIO or combo card that supplies the malformed CIS value, and recovery requires resetting the device.

CVSS severityUnavailable
Unscored
EPSS probability0.17%
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 3.6.0 through 4.4.1 allows physically proximate attackers to hang SDIO-dependent services. The byte-I/O loop in sdio_io_rw_extended_helper() uses an unvalidated card-supplied maximum block size as its step, so zero leaves the remaining length unchanged while the card mutex stays locked. Exploitation requires a removable SDIO or combo card that supplies the malformed CIS value, and recovery requires resetting the device.

The record

CVE
CVE-2026-15923
Published
Sep 14, 2026
Updated
Sep 14, 2026
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
Unavailable
Attack vector
physical
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 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?

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

  1. Affected versionversion=3.6.0 <4.4.2

What conditions does exploitation require?

Attack vectorphysical
Required privilegesUnavailable in this record.

What is affected?

Zephyr Project · Zephyr RTOSversion=3.6.0 <4.4.2

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

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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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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