{"api_version":"1","generated_at":"2026-09-13T13:17:21+00:00","cve":"CVE-2026-13343","urls":{"html":"https://cve.report/CVE-2026-13343","api":"https://cve.report/api/cve/CVE-2026-13343.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-13343","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-13343"},"summary":{"title":"Uninitialised stack memory disclosure in the MIDI 2.0 UMP Stream responder","description":"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.\n\nEndpoint 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.\n\nEach 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.\n\nThe 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.","state":"PUBLISHED","assigner":"zephyr","published_at":"2026-08-24 16:16:55","updated_at":"2026-08-26 16:59:23"},"problem_types":["CWE-200","CWE-200 info-leak"],"metrics":[{"version":"3.1","source":"vulnerabilities@zephyrproject.org","type":"Secondary","score":"5.3","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","baseScore":5.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"NONE","availabilityImpact":"NONE"}},{"version":"3.1","source":"CNA","type":"CVSS","score":"5.3","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","data":{"baseScore":5.3,"baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","version":"3.1"}}],"references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-4w5x-w7j4-6xxc","name":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-4w5x-w7j4-6xxc","refsource":"vulnerabilities@zephyrproject.org","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/255e64bd22fcd02bd437bb0d6badac87c67de23b","name":"https://github.com/zephyrproject-rtos/zephyr/commit/255e64bd22fcd02bd437bb0d6badac87c67de23b","refsource":"vulnerabilities@zephyrproject.org","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-13343","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-13343","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"zephyrproject","product":"zephyr","version":"affected 4.3.0 4.4.2 semver","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"13343","cve":"CVE-2026-13343","epss":"0.002340000","percentile":"0.140900000","score_date":"2026-08-27","updated_at":"2026-08-28 00:03:41"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-13343","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2026-08-24T20:20:21.608785Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2026-08-24T20:20:44.618Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"collectionURL":"https://github.com/zephyrproject-rtos/zephyr","defaultStatus":"unaffected","packageName":"zephyr","product":"zephyr","programFiles":["lib/midi2/ump_stream_responder.c"],"vendor":"zephyrproject","versions":[{"lessThan":"4.4.2","status":"affected","version":"4.3.0","versionType":"semver"}]}],"descriptions":[{"lang":"en","value":"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.\n\nEndpoint 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.\n\nEach 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.\n\nThe 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."}],"metrics":[{"cvssV3_1":{"baseScore":5.3,"baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","version":"3.1"},"format":"CVSS"}],"problemTypes":[{"descriptions":[{"cweId":"CWE-200","description":"info-leak","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-08-24T15:43:36.665Z","orgId":"e2e69745-5e70-4e92-8431-deb5529a81ad","shortName":"zephyr"},"references":[{"name":"Fix commit","tags":["patch"],"url":"https://github.com/zephyrproject-rtos/zephyr/commit/255e64bd22fcd02bd437bb0d6badac87c67de23b"},{"name":"GHSA-4w5x-w7j4-6xxc","url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-4w5x-w7j4-6xxc"}],"title":"Uninitialised stack memory disclosure in the MIDI 2.0 UMP Stream responder","x_generator":{"engine":"cvelib 1.8.0"}}},"cveMetadata":{"assignerOrgId":"e2e69745-5e70-4e92-8431-deb5529a81ad","assignerShortName":"zephyr","cveId":"CVE-2026-13343","datePublished":"2026-08-24T15:43:36.665Z","dateReserved":"2026-06-25T14:13:05.267Z","dateUpdated":"2026-08-24T20:20:44.618Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-24 16:16:55","lastModifiedDate":"2026-08-26 16:59:23","problem_types":["CWE-200","CWE-200 info-leak"],"metrics":{"cvssMetricV31":[{"source":"vulnerabilities@zephyrproject.org","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","baseScore":5.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"NONE","availabilityImpact":"NONE"},"exploitabilityScore":3.9,"impactScore":1.4}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-08-24T20:20:21.608785Z","id":"CVE-2026-13343","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"13343","Ordinal":"1","Title":"Uninitialised stack memory disclosure in the MIDI 2.0 UMP Stream","CVE":"CVE-2026-13343","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"13343","Ordinal":"1","NoteData":"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.\n\nEndpoint 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.\n\nEach 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.\n\nThe 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.","Type":"Description","Title":"Uninitialised stack memory disclosure in the MIDI 2.0 UMP Stream"}]}}}