GHSA-C29C-H3VQ-MR67

Vulnerability from github – Published: 2026-08-28 09:31 – Updated: 2026-08-28 09:31
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

drm/vmwgfx: validate external BO copy bounds for both stride paths

vmw_external_bo_copy() trusts caller-supplied offsets, strides, and heights and operates on imported dma-buf vmaps:

  • The equal-stride memcpy() bound was clamped after subtracting the offsets from dst_size and src_size; an offset larger than the BO size wraps the unsigned subtraction to a huge value and the resulting memcpy() runs off the end of the vmap. dst_stride * height is also a u32 multiplication that can overflow.
  • The non-equal-stride row-by-row path had no bound at all. The loop touches bytes through offset + (height - 1) * stride + width_in_bytes, with only a WARN_ON(dst_stride < width_in_bytes), and could likewise step past the end of either mapping.

The offsets and strides are derived from STDU/SOU plane state, so a configured CRTC submitting a crafted atomic commit on an imported framebuffer can reach this path.

Validate the exact row-copy endpoint against each BO's size up front using check_mul_overflow() and check_add_overflow(). Use the bulk memcpy() path only when width_in_bytes covers the whole stride; otherwise copy one row at a time so partial-row updates near the bottom of a framebuffer remain valid. Also reject zero strides and stride < width_in_bytes, both of which the row-by-row path cannot represent safely.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-80700"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-28T08:16:55Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/vmwgfx: validate external BO copy bounds for both stride paths\n\nvmw_external_bo_copy() trusts caller-supplied offsets, strides, and\nheights and operates on imported dma-buf vmaps:\n\n  - The equal-stride memcpy() bound was clamped after subtracting the\n    offsets from dst_size and src_size; an offset larger than the BO\n    size wraps the unsigned subtraction to a huge value and the\n    resulting memcpy() runs off the end of the vmap.  dst_stride *\n    height is also a u32 multiplication that can overflow.\n  - The non-equal-stride row-by-row path had no bound at all.  The\n    loop touches bytes through offset + (height - 1) * stride +\n    width_in_bytes, with only a WARN_ON(dst_stride \u003c width_in_bytes),\n    and could likewise step past the end of either mapping.\n\nThe offsets and strides are derived from STDU/SOU plane state, so a\nconfigured CRTC submitting a crafted atomic commit on an imported\nframebuffer can reach this path.\n\nValidate the exact row-copy endpoint against each BO\u0027s size up front\nusing check_mul_overflow() and check_add_overflow().  Use the bulk\nmemcpy() path only when width_in_bytes covers the whole stride;\notherwise copy one row at a time so partial-row updates near the bottom\nof a framebuffer remain valid.  Also reject zero strides and stride \u003c\nwidth_in_bytes, both of which the row-by-row path cannot represent\nsafely.",
  "id": "GHSA-c29c-h3vq-mr67",
  "modified": "2026-08-28T09:31:49Z",
  "published": "2026-08-28T09:31:49Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80700"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/042ca38779554687fc32b66a28328e0d9a36c58f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4e0f669e2951b742239c6fe847fcc406fe78748d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5e4a2d15637a906cbd9bc98e0bf969f5f713e344"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/706c93c5813caabbb0d0a576c017d15aeec2c113"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e7b25a6011781ebfdbc458552cae6d4156732771"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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