{"id":"CVE-2026-12051","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-12051","generatedAt":"2026-10-28T03:42:42.822Z","title":"The result is a NULL+offset read that triggers a fatal CPU fault, i.e. a denial of service (device crash/reset).","description":"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 — 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.","published":"2026-08-11T06:17:13.000Z","lastModified":"2026-10-23T19:10:00.000Z","status":"Awaiting Analysis","sourceIdentifier":"vulnerabilities@zephyrproject.org","cvss":{"version":"3.1","score":4.6,"severity":"MEDIUM","vector":"CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-476"],"affected":[],"epss":{"score":0.0023,"percentile":0.13793,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.23%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"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"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-12051","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}