CVE-2026-12051
NULL pointer dereference in USB DFU device_next download handler (handle_download)
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. 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.
INFO
Published Date :
Aug. 11, 2026, 6:17 a.m.
Last Modified :
Aug. 11, 2026, 6:17 a.m.
Remotely Exploit :
No
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-12051
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | e2e69745-5e70-4e92-8431-deb5529a81ad | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Ensure the USB DFU class handler checks for NULL buffers.
- Update to a patched version of the Zephyr device stack.
- Avoid processing DFU download requests with NULL buffers.
- Disable DFU download functionality if not required.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-12051.
| URL | Resource |
|---|---|
| https://github.com/zephyrproject-rtos/zephyr/commit/552ca371257597b71490482d5cc597157ea60f12 | |
| https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-vhvq-q6rw-jvm4 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-12051 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-12051
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-12051 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-12051 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Aug. 11, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'zephyrproject', 'product': 'zephyr', 'versions': [{'status': 'affected', 'version': '4.4.0', 'lessThan': '4.5.0', 'versionType': 'semver'}], 'packageName': 'zephyr', 'programFiles': ['subsys/usb/device_next/class/usbd_dfu.c'], 'collectionURL': 'https://github.com/zephyrproject-rtos/zephyr', 'defaultStatus': 'unaffected'}] Added 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. 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. Added CVSS V3.1 AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-476 Added Reference https://github.com/zephyrproject-rtos/zephyr/commit/552ca371257597b71490482d5cc597157ea60f12 Added Reference https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-vhvq-q6rw-jvm4