FKIE_CVE-2026-46209

Vulnerability from fkie_nvd - Published: 2026-05-28 10:16 - Updated: 2026-05-28 13:44
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: drm/gem: Fix inconsistent plane dimension calculation in drm_gem_fb_init_with_funcs() drm_gem_fb_init_with_funcs() computes sub-sampled plane dimensions using plain integer division: unsigned int width = mode_cmd->width / (i ? info->hsub : 1); unsigned int height = mode_cmd->height / (i ? info->vsub : 1); However, the ioctl-level framebuffer_check() in drm_framebuffer.c uses drm_format_info_plane_width/height() which round up dimensions via DIV_ROUND_UP(). This inconsistency corrupts the subsequent GEM object size check for certain pixel format and dimension combinations. For example, with NV12 (vsub=2) and a 1-pixel-tall framebuffer the GEM size validation path sees height=0 instead of height=1. The expression (height - 1) then wraps to UINT_MAX as an unsigned int, causing min_size to overflow and wrap back to a small value. A tiny GEM object therefore passes the size guard, yet when the GPU accesses the chroma plane it will read or write memory beyond the object's bounds. Fix by replacing the open-coded divisions with drm_format_info_plane_width() and drm_format_info_plane_height(), which use DIV_ROUND_UP() and match the calculation already used in framebuffer_check().
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1a17ea9861e89585361caa8bc231bd22dc6dbe7d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1da4ab7189f1064b3b712b388772c008b4d82580
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3d4c2268bd7243c3780fe32bf24ff876da272acf
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6b992591e04f2cce813bcf239b354f375bbf84d3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c5fc49d8470c5ebf3b41607600f277158f159950
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/gem: Fix inconsistent plane dimension calculation in drm_gem_fb_init_with_funcs()\n\ndrm_gem_fb_init_with_funcs() computes sub-sampled plane dimensions\nusing plain integer division:\n\n  unsigned int width  = mode_cmd-\u003ewidth  / (i ? info-\u003ehsub : 1);\n  unsigned int height = mode_cmd-\u003eheight / (i ? info-\u003evsub : 1);\n\nHowever, the ioctl-level framebuffer_check() in drm_framebuffer.c uses\ndrm_format_info_plane_width/height() which round up dimensions via\nDIV_ROUND_UP(). This inconsistency corrupts the subsequent GEM object\nsize check for certain pixel format and dimension combinations.\n\nFor example, with NV12 (vsub=2) and a 1-pixel-tall framebuffer the\nGEM size validation path sees height=0 instead of height=1. The\nexpression (height - 1) then wraps to UINT_MAX as an unsigned int,\ncausing min_size to overflow and wrap back to a small value. A tiny\nGEM object therefore passes the size guard, yet when the GPU accesses\nthe chroma plane it will read or write memory beyond the object\u0027s\nbounds.\n\nFix by replacing the open-coded divisions with drm_format_info_plane_width()\nand drm_format_info_plane_height(), which use DIV_ROUND_UP() and match\nthe calculation already used in framebuffer_check()."
    }
  ],
  "id": "CVE-2026-46209",
  "lastModified": "2026-05-28T13:44:01.663",
  "metrics": {},
  "published": "2026-05-28T10:16:36.567",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1a17ea9861e89585361caa8bc231bd22dc6dbe7d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1da4ab7189f1064b3b712b388772c008b4d82580"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3d4c2268bd7243c3780fe32bf24ff876da272acf"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6b992591e04f2cce813bcf239b354f375bbf84d3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c5fc49d8470c5ebf3b41607600f277158f159950"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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