{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "76c072b48e39e9291fbf02d6c912cf27d65e093d"
            },
            {
              "fixed": "aaa93e41ae308ad9ff9d9ba3296a0d0f4d45bad3"
            },
            {
              "fixed": "f171054f3c4cfc4dc0cb622ec5b15793e5f23029"
            },
            {
              "fixed": "afe80ec31464f4c54cc1bc658753bc14cb14bd6c"
            },
            {
              "fixed": "98195e822343a656b92e235847ab3e72b1a3f920"
            },
            {
              "fixed": "e5c3f3d8935ecc64c962fb66e6a86dbf79218f61"
            },
            {
              "fixed": "5680b6fb3054677d4ee65d3baba24b649f1b430e"
            },
            {
              "fixed": "725b49c689bbb29ef740b0d6b5ea9390baa9a695"
            },
            {
              "fixed": "9b3fcf519d370df94a56f3b272d9eddffffa5be8"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.6.25"
            },
            {
              "fixed": "5.10.273"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.224"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.191"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.160"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.113"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.57"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/99xxx/CVE-2026-99063.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndm ioctl: don't let data_start run past the buffer\n\nstruct dm_ioctl has seven bytes of trailing padding, so the smallest\nbuffer userspace is allowed to ask for, offsetof(struct dm_ioctl, data),\nis seven bytes shorter than sizeof(struct dm_ioctl).\n\nget_result_buffer() sets data_start to sizeof(struct dm_ioctl) without\nlooking at how big the buffer actually is. Ask for the minimum and\ndata_start ends up seven bytes past the end. Callers add it to\ndata_size, and ctl_ioctl() copies that much back to userspace:\n\n  BUG: KASAN: slab-out-of-bounds in _copy_to_user+0xad/0xd0\n  Read of size 312 at addr ffff8880169e4c00 by task repro-dm/140\n   ctl_ioctl+0x5e3/0xcb0\n   dm_ctl_ioctl+0x25/0x40\n  allocated 305-byte region [ffff8880169e4c00, ffff8880169e4d31)\n\nA DM_LIST_DEVICES with data_size set to 305 is enough to hit it, and the\nseven bytes that leak are whatever sat next to the allocation.\n\nClamp data_start to the buffer size.\n\nNote that this is not a security bug because the out-of-bounds read can\nonly be triggered by root.",
  "id": "CVE-2026-99063",
  "modified": "2026-11-01T02:31:06.540066888Z",
  "published": "2026-10-23T12:23:04.655Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5680b6fb3054677d4ee65d3baba24b649f1b430e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/725b49c689bbb29ef740b0d6b5ea9390baa9a695"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/98195e822343a656b92e235847ab3e72b1a3f920"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9b3fcf519d370df94a56f3b272d9eddffffa5be8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/aaa93e41ae308ad9ff9d9ba3296a0d0f4d45bad3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/afe80ec31464f4c54cc1bc658753bc14cb14bd6c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e5c3f3d8935ecc64c962fb66e6a86dbf79218f61"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f171054f3c4cfc4dc0cb622ec5b15793e5f23029"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/99xxx/CVE-2026-99063.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99063"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.2",
  "summary": "dm ioctl: don't let data_start run past the buffer"
}