Vulnerability-Lookup

CVE-2026-13343 (GCVE-0-2026-13343)

Vulnerability from cvelistv5 – Published: 2026-08-24 15:43 – Updated: 2026-08-24 20:20

Title

Uninitialised stack memory disclosure in the MIDI 2.0 UMP Stream responder

Summary

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.

Severity

5.3 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-24 20:20 UTC

CWE

CWE-200 - info-leak

Assigner

zephyr mitre root

References

2 references

URL	Tags
https://github.com/zephyrproject-rtos/zephyr/comm…	patch
https://github.com/zephyrproject-rtos/zephyr/secu…

Impacted products

1 product

Vendor	Product	Version	CPE status
zephyrproject	zephyr	Affected: 4.3.0 , < 4.4.2 (semver)	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-13343

Vulnerability from fkie_nvd - Published: 2026-08-24 16:16 - Updated: 2026-08-24 21:16

Severity

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

Summary

References

	URL	Tags
	vulnerabilities@zephyrproject.org	https://github.com/zephyrproject-rtos/zephyr/commit/255e64bd22fcd02bd437bb0d6badac87c67de23b
	vulnerabilities@zephyrproject.org	https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-4w5x-w7j4-6xxc

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
          "defaultStatus": "unaffected",
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          "product": "zephyr",
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            "lib/midi2/ump_stream_responder.c"
          ],
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          "versions": [
            {
              "lessThan": "4.4.2",
              "status": "affected",
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            }
          ]
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      ],
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    }
  ],
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    }
  ],
  "id": "CVE-2026-13343",
  "lastModified": "2026-08-24T21:16:48.327",
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

CVE-2026-13343 (GCVE-0-2026-13343)

FKIE_CVE-2026-13343

Tags

Sightings

Nomenclature