{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-23238",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2026-23238"
  ],
  "published": "2026-03-04T14:38:44Z",
  "summary": "romfs: check sb_set_blocksize() return value",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nromfs: check sb_set_blocksize() return value\n\nromfs_fill_super() ignores the return value of sb_set_blocksize(), which\ncan fail if the requested block size is incompatible with the block\ndevice's configuration.\n\nThis can be triggered by setting a loop device's block size larger than\nPAGE_SIZE using ioctl(LOOP_SET_BLOCK_SIZE, 32768), then mounting a romfs\nfilesystem on that device.\n\nWhen sb_set_blocksize(sb, ROMBSIZE) is called with ROMBSIZE=4096 but the\ndevice has logical_block_size=32768, bdev_validate_blocksize() fails\nbecause the requested size is smaller than the device's logical block\nsize. sb_set_blocksize() returns 0 (failure), but romfs ignores this and\ncontinues mounting.\n\nThe superblock's block size remains at the device's logical block size\n(32768). Later, when sb_bread() attempts I/O with this oversized block\nsize, it triggers a kernel BUG in folio_set_bh():\n\n    kernel BUG at fs/buffer.c:1582!\n    BUG_ON(size > PAGE_SIZE);\n\nFix by checking the return value of sb_set_blocksize() and failing the\nmount with -EINVAL if it returns 0.",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.164",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-23238"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a381f0f61b35c8894b0bd0d6acef2d8f9b08b244"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/f2521ab1f63a8c244f06a080319e5ff9a2e1bd95"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/2c5829cd8fbbc91568c520b666898f57cdcb8cf6"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/cbd9931e6456822067725354d83446c5bb813030"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9b203b8ddd7359270e8a694d0584743555128e2c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/4b71ad7676564a94ec5f7d18298f51e8ae53db73"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ab7ad7abb3660c58ffffdf07ff3bb976e7e0afa0"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-05-12T04:54:46Z"
  }
}