accel/ethosu: fix OOB write in ethosu_gem_cmdstream_copy_and_validate()

{
  "id": "a6baec3486fc4c259d9d473cd35ba70cbafb81cdf06ce3cc71fd2fa0ecd0a85e",
  "url": "https://osv.dev/vulnerability/CVE-2026-53173",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "accel/ethosu: fix OOB write in ethosu_gem_cmdstream_copy_and_validate()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: accel/ethosu: fix OOB write in ethosu_gem_cmdstream_copy_and_validate() The command stream parsing loop increments the index variable a second time when a 64-bit command word is encountered (bit 14 set), but does not re-check the loop bound before writing the second word: for (i = 0; i < size / 4; i++) { bocmds[i] = cmds[0]; if (cmd & 0x4000) { i++; bocmds[i] = cmds[1]; /* unchecked */ } } The buffer bocmds is backed by a DMA allocation of exactly size bytes from drm_gem_dma_create(ddev, size), giving valid indices [0, size/4-1]. When i == size/4 - 1 on entry to an iteration and bit 14 of cmds[0] is set, bocmds[size/4-1] is written in bounds, i is then incremented to size/4, and bocmds[size/4] writes four bytes past the end of the allocation. Userspace controls both the buffer contents and the size argument via the ioctl, making this a userspace-triggerable heap out-of-bounds write. Fix by checking the incremented index against the buffer bound before the second write and returning -EINVAL if the buffer is too small to contain the extended command.",
    "evidence": "osv:CVE-2026-53173",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "7.0.13",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-53173",
      "aliases": [
        "CVE-2026-53173"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "5a5e9c0228e613f0ef2a58b9782d7c0ea8f1e58b"
                },
                {
                  "fixed": "db6cb3e35cebf487f9a78ebd4cfa4b83708ff40d"
                },
                {
                  "fixed": "c0837b9cf6eabbad8b8cbddaff1a46a6d0a2e29d"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53173.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.0.13"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53173.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:23.609303834Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/c0837b9cf6eabbad8b8cbddaff1a46a6d0a2e29d",
        "https://git.kernel.org/stable/c/db6cb3e35cebf487f9a78ebd4cfa4b83708ff40d",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53173.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-53173",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53173.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-53173",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 489874,
  "published_at": "2026-06-25T08:38:50.709+00:00"
}