CVE-2026-13343

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Source

https://cve.org/CVERecord?id=CVE-2026-13343

Import Source

https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-13343.json

JSON Data

https://api.osv.dev/v1/vulns/CVE-2026-13343

Aliases

GHSA-4w5x-w7j4-6xxc

Published

2026-08-24T15:43:36Z

Modified

2026-10-06T07:05:02Z

Severity

5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N CVSS Calculator

Summary

Uninitialised stack memory disclosure in the MIDI 2.0 UMP Stream responder

Details

The UMP Stream responder library in lib/midi2/ump_stream_responder.c builds reply packets in a 16-byte struct midi_ump (uint32_t data[4]). The builders make_endpoint_info() and make_function_block_info() populate only the first two words (res.data[0] and res.data[1]) and, before this fix, declared their result as an uninitialised local (struct midi_ump res;). The remaining two words (res.data[2], res.data[3]) retain stale stack contents.

Endpoint Info and Function Block Info notifications are UMP Stream messages (UMP_MT_UMP_STREAM), which are 4 words long, so the full 16-byte packet — including the two uninitialised words — is transmitted verbatim by cfg->send(). The responder is driven by attacker-supplied UMP Stream Endpoint-Discovery / Function-Block-Discovery requests via ump_stream_respond(). In the in-tree Network MIDI 2.0 server (subsys/net/lib/midi2/netmidi2.c) these requests arrive as UDP datagrams and, with the default no-authentication endpoint, a remote peer can establish a session and trigger the responses; the same library also serves USB MIDI 2.0 hosts.

Each discovery request causes the device to disclose 8 bytes of its own uninitialised stack memory to the peer, and the request is freely repeatable. This is a confidentiality-only information leak (root cause is use of an uninitialised variable, CWE-457/CWE-908); the leaked words could include residual data or pointer values. There is no memory-corruption, integrity, or availability impact.

The fix zero-initialises both result structs (struct midi_ump res = {0};), so the trailing words are cleared before transmission. These are the only two responder builders that left trailing words unset (send_string() already zeroes its buffer), so the leak is fully closed.

Database specific

{
    "cna_assigner": "zephyr",
    "cwe_ids": [
        "CWE-200"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/13xxx/CVE-2026-13343.json"
}

References

Affected packages

Git / github.com/zephyrproject-rtos/zephyr

Affected ranges

Type

GIT

Repo

https://github.com/zephyrproject-rtos/zephyr

Events

Introduced

3568e1b6d5cdd51a6b964a2a1d6d29200fea2056

Fixed

255e64bd22fcd02bd437bb0d6badac87c67de23b

Database specific

Show details

{
    "extracted_events": [
        {
            "introduced": "4.3.0"
        },
        {
            "fixed": "4.4.2"
        }
    ],
    "source": [
        "AFFECTED_FIELD",
        "REFERENCES"
    ]
}

Affected versions

v4.*

v4.3.0

v4.4.0

v4.4.0-rc1

v4.4.0-rc2

v4.4.0-rc3

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-13343.json"

vanir_signatures

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        "signature_version": "v1",
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        "target": {
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vanir_signatures_modified

"2026-10-06T07:05:02Z"