CVE-2026-12051

{"id": "CVE-2026-12051", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-12051", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-08-11T14:22:41.005101Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "vulnerabilities@zephyrproject.org", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 4.6, "attackVector": "PHYSICAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 0.9}]}, "affected": [{"source": "vulnerabilities@zephyrproject.org", "affectedData": [{"vendor": "zephyrproject", "product": "zephyr", "versions": [{"status": "affected", "version": "4.4.0", "lessThan": "4.4.2", "versionType": "semver"}], "packageName": "zephyr", "programFiles": ["subsys/usb/device_next/class/usbd_dfu.c"], "collectionURL": "https://github.com/zephyrproject-rtos/zephyr", "defaultStatus": "unaffected"}]}], "published": "2026-08-11T06:17:12.620", "references": [{"url": "https://github.com/zephyrproject-rtos/zephyr/commit/552ca371257597b71490482d5cc597157ea60f12", "source": "vulnerabilities@zephyrproject.org"}, {"url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-vhvq-q6rw-jvm4", "source": "vulnerabilities@zephyrproject.org"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "vulnerabilities@zephyrproject.org", "description": [{"lang": "en", "value": "CWE-476"}]}], "descriptions": [{"lang": "en", "value": "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->wLength, buf->len) and passes buf->data 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 \u2014 notably the zero-length terminating download that the DFU protocol uses to end a firmware transfer \u2014 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 \u2014 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."}, {"lang": "es", "value": "La implementaci\u00f3n de la clase USB DFU en la nueva (experimental) pila de dispositivos USB device_next de Zephyr contiene una desreferencia de puntero NULL en handle_download() (subsys/usb/device_next/class/usbd_dfu.c). El gestor calcula MIN(setup -> wLength, buf -> len) y pasa buf -> data a la funci\u00f3n de devoluci\u00f3n de llamada de escritura de imagen sin verificar que el puntero net_buf de buf no sea NULL.\n\nSe accede al gestor a trav\u00e9s del punto final de control USB, impulsado por el host USB. Para una solicitud DFU_DNLOAD (descarga) sin una etapa de salida de datos (Data OUT) - en particular, la descarga de terminaci\u00f3n de longitud cero que el protocolo DFU utiliza para finalizar una transferencia de firmware - el n\u00facleo USB invoca al gestor de clase con un b\u00fafer NULL. Despu\u00e9s de que el dispositivo ha avanzado al estado DFU_DNLOAD_IDLE (enviando un bloque de descarga v\u00e1lido y un GET_STATUS), una DFU_DNLOAD de longitud cero llega a handle_download() con buf == NULL, desreferenci\u00e1ndolo.\n\nEl resultado es una lectura NULL+offset que desencadena un fallo fatal de la CPU, es decir, una denegaci\u00f3n de servicio (bloqueo/reinicio del dispositivo). El atacante es quien controla el host USB al que est\u00e1 conectado el dispositivo; el soporte de descarga DFU debe estar habilitado con una imagen registrada. No hay corrupci\u00f3n de memoria ni revelaci\u00f3n de informaci\u00f3n - el impacto se limita a la disponibilidad. La soluci\u00f3n a\u00f1ade una protecci\u00f3n expl\u00edcita if (buf != NULL) para que la funci\u00f3n de devoluci\u00f3n de llamada reciba una transferencia de longitud cero y datos NULL en lugar de bloquearse."}], "lastModified": "2026-10-23T19:10:00.167", "sourceIdentifier": "vulnerabilities@zephyrproject.org"}