{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-53130",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-53130"
  ],
  "published": "2026-06-24T16:31:02Z",
  "summary": "fs/omfs: reject s_sys_blocksize smaller than OMFS_DIR_START",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/omfs: reject s_sys_blocksize smaller than OMFS_DIR_START\n\nomfs_fill_super() rejects oversized s_sys_blocksize values (> PAGE_SIZE),\nbut it does not reject values smaller than OMFS_DIR_START (0x1b8 = 440).\n\nLater, omfs_make_empty() uses\n\n    sbi->s_sys_blocksize - OMFS_DIR_START\n\nas the length argument to memset().  Since s_sys_blocksize is u32,\na crafted filesystem image with s_sys_blocksize < OMFS_DIR_START causes\nan unsigned underflow there, wrapping to a value near 2^32.  That drives\na ~4 GiB memset() from bh->b_data + OMFS_DIR_START and overwrites kernel\nmemory far beyond the backing block buffer.\n\nAdd the corresponding lower-bound check alongside the existing upper-bound\ncheck in omfs_fill_super(), so that malformed images are rejected during\nsuperblock validation before any filesystem data is processed.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"
    }
  ],
  "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": "6.1.175",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-53130"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/fbc72f5c645155dc2ed3573243ed20f9913e3a54"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/5822a05a841a10794ad818620dd2af490b0705d3"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/754ff1bea3819a90c6f33cccfc1a299ef7609f07"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/131ea3e57fc22936ed0e2c8330f2e36106172f51"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/79f84af38c9fef9deb0e02c79eb969b5541c2644"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/6561afc38398e3518a29c5eebb975c30468f98a6"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/817f16ed62bc58a168417bfb5e859c2a370bab03"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/0621c385fda1376e967f37ccd534c26c3e511d14"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T13:16:28Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - Exploitation requires a crafted OMFS block filesystem image to be mounted and then operated on locally; there is no network packet or adjacent-radio path into this filesystem code.\nAC:L - A crafted image with s_sys_blocksize below OMFS_DIR_START can deterministically reach the underflow when a directory is created; there is no race or condition outside attacker control beyond having OMFS support present.\nPR:N - Although direct self-mounting OMFS requires CAP_SYS_ADMIN in the initial namespace and is not reachable through user namespaces, the highest reasonable crafted-image scenario requires no attacker account or privileges and relies on a victim/privileged mount workflow.\nUI:R - A user or privileged automount-like workflow must mount the crafted OMFS image and perform an operation such as directory creation on it before omfs_make_empty() is reached.\nS:U - The corruption occurs within the Linux kernel on the same host security authority and does not cross a VM, IOMMU, or other scope boundary.\nC:H - The bug is a massive kernel out-of-bounds write, and successful exploitation of kernel memory corruption can yield kernel code execution or privilege escalation with access to confidential data.\nI:H - The unsigned underflow drives a near-4 GiB memset past the buffer_head data, corrupting arbitrary kernel memory beyond the filesystem buffer.\nA:H - The oversized kernel memset can corrupt critical memory and reliably cause an oops, panic, hang, or other full system denial of service."
    }
  }
}