{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2025-40216",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2025-40216"
  ],
  "published": "2025-12-04T14:14:24Z",
  "summary": "io_uring/rsrc: don't rely on user vaddr alignment",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/rsrc: don't rely on user vaddr alignment\n\nThere is no guaranteed alignment for user pointers, however the\ncalculation of an offset of the first page into a folio after coalescing\nuses some weird bit mask logic, get rid of it.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.12.20-1+rpt1~bpo12+1",
        "1:6.12.25-1+rpt1",
        "1:6.12.34-1+rpt1~bookworm"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.12.20+rpt-rpi-2712",
            "binary_version": "1:6.12.20-1+rpt1~bpo12+1"
          },
          {
            "binary_name": "linux-image-6.12.20+rpt-rpi-v6",
            "binary_version": "1:6.12.20-1+rpt1~bpo12+1"
          },
          {
            "binary_name": "linux-image-6.12.20+rpt-rpi-v7",
            "binary_version": "1:6.12.20-1+rpt1~bpo12+1"
          },
          {
            "binary_name": "linux-image-6.12.20+rpt-rpi-v7l",
            "binary_version": "1:6.12.20-1+rpt1~bpo12+1"
          },
          {
            "binary_name": "linux-image-6.12.20+rpt-rpi-v8",
            "binary_version": "1:6.12.20-1+rpt1~bpo12+1"
          },
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-2712",
            "binary_version": "1:6.12.25-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-v6",
            "binary_version": "1:6.12.25-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-v7",
            "binary_version": "1:6.12.25-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-v7l",
            "binary_version": "1:6.12.25-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-v8",
            "binary_version": "1:6.12.25-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.34+rpt-rpi-2712",
            "binary_version": "1:6.12.34-1+rpt1~bookworm"
          },
          {
            "binary_name": "linux-image-6.12.34+rpt-rpi-v6",
            "binary_version": "1:6.12.34-1+rpt1~bookworm"
          },
          {
            "binary_name": "linux-image-6.12.34+rpt-rpi-v7",
            "binary_version": "1:6.12.34-1+rpt1~bookworm"
          },
          {
            "binary_name": "linux-image-6.12.34+rpt-rpi-v7l",
            "binary_version": "1:6.12.34-1+rpt1~bookworm"
          },
          {
            "binary_name": "linux-image-6.12.34+rpt-rpi-v8",
            "binary_version": "1:6.12.34-1+rpt1~bookworm"
          },
          {
            "binary_name": "linux-image-6.12.34+rpt-rpi-v8-rt",
            "binary_version": "1:6.12.34-1+rpt1~bookworm"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.12.20-1+rpt1~bpo12+1": {
            "linux_commit": "cd231d4775b14f228606c09f219b48308f6ab3aa",
            "upstream_version": "6.12.20",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.12.36"
          },
          "1:6.12.25-1+rpt1": {
            "linux_commit": "3dd2c2c507c271d411fab2e82a2b3b7e0b6d3f16",
            "upstream_version": "6.12.25",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.12.36"
          },
          "1:6.12.34-1+rpt1~bookworm": {
            "linux_commit": "8f77e03530f65209a377d25023e912b288e039cd",
            "upstream_version": "6.12.34",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.12.36"
          }
        }
      }
    },
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:13",
        "name": "linux"
      },
      "versions": [
        "1:6.12.19-1+rpt1~bpo12+1",
        "1:6.12.19-1+rpt1",
        "1:6.12.20-1+rpt1",
        "1:6.12.25-1+rpt1+trixie",
        "1:6.12.34-1+rpt1"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.12.19+rpt-rpi-2712",
            "binary_version": "1:6.12.19-1+rpt1~bpo12+1"
          },
          {
            "binary_name": "linux-image-6.12.19+rpt-rpi-v6",
            "binary_version": "1:6.12.19-1+rpt1~bpo12+1"
          },
          {
            "binary_name": "linux-image-6.12.19+rpt-rpi-v7",
            "binary_version": "1:6.12.19-1+rpt1~bpo12+1"
          },
          {
            "binary_name": "linux-image-6.12.19+rpt-rpi-v7l",
            "binary_version": "1:6.12.19-1+rpt1~bpo12+1"
          },
          {
            "binary_name": "linux-image-6.12.19+rpt-rpi-v8",
            "binary_version": "1:6.12.19-1+rpt1~bpo12+1"
          },
          {
            "binary_name": "linux-image-6.12.19+rpt-rpi-2712",
            "binary_version": "1:6.12.19-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.19+rpt-rpi-v6",
            "binary_version": "1:6.12.19-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.19+rpt-rpi-v7",
            "binary_version": "1:6.12.19-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.19+rpt-rpi-v7l",
            "binary_version": "1:6.12.19-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.19+rpt-rpi-v8",
            "binary_version": "1:6.12.19-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.20+rpt-rpi-2712",
            "binary_version": "1:6.12.20-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.20+rpt-rpi-v6",
            "binary_version": "1:6.12.20-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.20+rpt-rpi-v7",
            "binary_version": "1:6.12.20-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.20+rpt-rpi-v7l",
            "binary_version": "1:6.12.20-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.20+rpt-rpi-v8",
            "binary_version": "1:6.12.20-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-2712",
            "binary_version": "1:6.12.25-1+rpt1+trixie"
          },
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-v6",
            "binary_version": "1:6.12.25-1+rpt1+trixie"
          },
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-v7",
            "binary_version": "1:6.12.25-1+rpt1+trixie"
          },
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-v8",
            "binary_version": "1:6.12.25-1+rpt1+trixie"
          },
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-v8-rt",
            "binary_version": "1:6.12.25-1+rpt1+trixie"
          },
          {
            "binary_name": "linux-image-6.12.34+rpt-rpi-2712",
            "binary_version": "1:6.12.34-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.34+rpt-rpi-v6",
            "binary_version": "1:6.12.34-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.34+rpt-rpi-v7",
            "binary_version": "1:6.12.34-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.34+rpt-rpi-v8",
            "binary_version": "1:6.12.34-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.34+rpt-rpi-v8-rt",
            "binary_version": "1:6.12.34-1+rpt1"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.12.19-1+rpt1~bpo12+1": {
            "linux_commit": "121c2c384b9c2f4790ffb31b2cd25c7d75c8fda0",
            "upstream_version": "6.12.19",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.12.36"
          },
          "1:6.12.19-1+rpt1": {
            "linux_commit": "121c2c384b9c2f4790ffb31b2cd25c7d75c8fda0",
            "upstream_version": "6.12.19",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.12.36"
          },
          "1:6.12.20-1+rpt1": {
            "linux_commit": "cd231d4775b14f228606c09f219b48308f6ab3aa",
            "upstream_version": "6.12.20",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.12.36"
          },
          "1:6.12.25-1+rpt1+trixie": {
            "linux_commit": "3dd2c2c507c271d411fab2e82a2b3b7e0b6d3f16",
            "upstream_version": "6.12.25",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.12.36"
          },
          "1:6.12.34-1+rpt1": {
            "linux_commit": "8f77e03530f65209a377d25023e912b288e039cd",
            "upstream_version": "6.12.34",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.12.36"
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-40216"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/50998b0ae7d9d552e96d8b7239981cf05f65eff5"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/f16769241594be59387b56ab525e327f54377e60"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/3a3c6d61577dbb23c09df3e21f6f9eda1ecd634b"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T12:19:11Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The vulnerable code is reached only through io_uring syscalls (io_uring_setup/io_uring_register with IORING_REGISTER_BUFFERS), which require local access; there is no network reachability.\nAC:L - The attacker fully controls the trigger \u2014 allocating a multi-page folio (mTHP/hugetlb) and creating a VA-vs-folio misalignment, then registering it \u2014 with no race or externally-determined condition, making it deterministically reproducible.\nPR:L - IORING_REGISTER_BUFFERS has no capability check and io_uring is available to unprivileged users by default; a basic local user can register a coalescable large-folio buffer.\nUI:N - The entire flow (map memory, register buffer, submit fixed I/O) is performed by the attacker's own process with no victim interaction.\nS:U - The corruption stays within the kernel's own security scope; there is no VM/IOMMU/sandbox boundary being crossed.\nC:H - The wrong bv_offset plus mis-driven seg_skip/nr_segs arithmetic can read out of the bvec array and at unintended folio offsets (including shared file-backed folios), disclosing kernel heap and cross-mapping memory.\nI:H - WRITE_FIXED with the miscomputed offset writes attacker-supplied I/O data at wrong offsets and potential wild page pointers, giving an out-of-bounds write / memory-corruption primitive.\nA:H - Dereferencing a garbage bio_vec / wild bv_page during fixed-buffer I/O readily oopses or panics the kernel."
    }
  }
}