CVE-2026-13343Network attack vector

Stack memory disclosure via uninitialized UMP replies

Published Aug 24, 2026 · Updated Aug 24, 2026

Information disclosure in Zephyr RTOS 4.3.0 through 4.4.1 allows remote attackers to read stack memory via UMP discovery requests. make_endpoint_info() and make_function_block_info() initialize only half of each 16-byte reply, so cfg->send() transmits eight stale stack bytes. Network MIDI 2.0 deployments accept the triggering UDP requests without authentication; repeated requests expose residual data or pointers without modifying memory or interrupting service.

CVSS severityUnavailable
Unscored
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

Information disclosure in Zephyr RTOS 4.3.0 through 4.4.1 allows remote attackers to read stack memory via UMP discovery requests. make_endpoint_info() and make_function_block_info() initialize only half of each 16-byte reply, so cfg->send() transmits eight stale stack bytes. Network MIDI 2.0 deployments accept the triggering UDP requests without authentication; repeated requests expose residual data or pointers without modifying memory or interrupting service.

The record

CVE
CVE-2026-13343
Published
Aug 24, 2026
Updated
Aug 24, 2026
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-908, CWE-457, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 24, 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=4.3.0 <4.4.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=4.3.0 <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

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-908Use of Uninitialized Resource
CWE-457Use of Uninitialized Variable
T1190Exploit Public-Facing Application

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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