CVE-2026-12051 (GCVE-0-2026-12051)

Vulnerability from cvelistv5 – Published: 2026-08-11 05:31 – Updated: 2026-08-31 23:13
VLAI
Title
NULL pointer dereference in USB DFU device_next download handler (handle_download)
Summary
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. The 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. The 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.
Severity
4.6 (Medium)
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-11 14:22 UTC
CWE
Assigner
zephyr CNA under the mitre root
CNA scorecard B 77/100 over 179 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
zephyrproject zephyr Affected: 4.4.0 , < 4.4.2 (semver)
guessed Create a notification for this product.
Show details on NVD website
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