FKIE_CVE-2026-12051

Vulnerability from fkie_nvd - Published: 2026-08-11 06:17 - Updated: 2026-09-01 00:16
Severity
4.6 (Medium) - CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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.
References
vulnerabilities@zephyrproject.orghttps://github.com/zephyrproject-rtos/zephyr/commit/552ca371257597b71490482d5cc597157ea60f12
vulnerabilities@zephyrproject.orghttps://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-vhvq-q6rw-jvm4
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
          "defaultStatus": "unaffected",
          "packageName": "zephyr",
          "product": "zephyr",
          "programFiles": [
            "subsys/usb/device_next/class/usbd_dfu.c"
          ],
          "vendor": "zephyrproject",
          "versions": [
            {
              "lessThan": "4.4.2",
              "status": "affected",
              "version": "4.4.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "vulnerabilities@zephyrproject.org"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "The USB DFU class implementation in Zephyr\u0027s 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 \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."
    }
  ],
  "id": "CVE-2026-12051",
  "lastModified": "2026-09-01T00:16:42.720",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "PHYSICAL",
          "availabilityImpact": "HIGH",
          "baseScore": 4.6,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 0.9,
        "impactScore": 3.6,
        "source": "vulnerabilities@zephyrproject.org",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-12051",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-11T14:22:41.005101Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-11T06:17:12.620",
  "references": [
    {
      "source": "vulnerabilities@zephyrproject.org",
      "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"
    }
  ],
  "sourceIdentifier": "vulnerabilities@zephyrproject.org",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
        }
      ],
      "source": "vulnerabilities@zephyrproject.org",
      "type": "Secondary"
    }
  ]
}



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