{"id":"CVE-2026-12051","summary":"NULL pointer dereference in USB DFU device_next download handler (handle_download)","details":"The USB DFU class implementation in Zephyr's new (experimental) device_next USB device stack contains a NULL pointer dereference in handle_download() (subsys/usb/device_next/class/usbd_dfu.c). The handler computes MIN(setup-\u003ewLength, buf-\u003elen) and passes buf-\u003edata to the image write callback without checking that the buf net_buf pointer is non-NULL.\n\nThe handler is reached over the USB control endpoint, driven by the USB host. For a DFU_DNLOAD (download) request with no Data OUT stage — notably the zero-length terminating download that the DFU protocol uses to end a firmware transfer — the USB core invokes the class handler with a NULL buffer. After the device has been advanced to the DFU_DNLOAD_IDLE state (by sending one valid download block and a GET_STATUS), a zero-length DFU_DNLOAD reaches handle_download() with buf == NULL, dereferencing it.\n\nThe result is a NULL+offset read that triggers a fatal CPU fault, i.e. a denial of service (device crash/reset). The attacker is whatever controls the USB host the device is attached to; DFU download support must be enabled with a registered image. There is no memory corruption or information disclosure — impact is limited to availability. The fix adds an explicit if (buf != NULL) guard so the callback receives a zero-length, NULL-data transfer instead of crashing.","aliases":["GHSA-vhvq-q6rw-jvm4"],"modified":"2026-09-02T08:05:45.933500Z","published":"2026-08-11T05:31:19.009Z","database_specific":{"cna_assigner":"zephyr","cwe_ids":["CWE-476"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/12xxx/CVE-2026-12051.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/12xxx/CVE-2026-12051.json"},{"type":"ADVISORY","url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-vhvq-q6rw-jvm4"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-12051"},{"type":"FIX","url":"https://github.com/zephyrproject-rtos/zephyr/commit/552ca371257597b71490482d5cc597157ea60f12"},{"type":"PACKAGE","url":"https://github.com/zephyrproject-rtos/zephyr"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/zephyrproject-rtos/zephyr","events":[{"introduced":"684c9e8f32e4373a21098559f748f06915f950c9"},{"fixed":"552ca371257597b71490482d5cc597157ea60f12"}],"database_specific":{"extracted_events":[{"introduced":"4.4.0"},{"fixed":"4.4.2"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["v4.4.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-12051.json","vanir_signatures_modified":"2026-09-02T08:05:45Z","vanir_signatures":[{"digest":{"line_hashes":["51695995382540564724771539224986601309","234033040335975934430491510740375948573","261489404340916789900145769588812295340","106914763439782829593453702443344437153","41266411084202754488436768641405680276","315809052901959911278253377441048002412"],"threshold":0.9},"id":"CVE-2026-12051-5ffcdca5","signature_type":"Line","signature_version":"v1","source":"https://github.com/zephyrproject-rtos/zephyr/commit/552ca371257597b71490482d5cc597157ea60f12","target":{"file":"subsys/usb/device_next/class/usbd_dfu.c"},"deprecated":false}]}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}