block: reject polled dio with user integrity metadata

{
  "id": "46908ec956cb124f44d927de7bebdbabfe5d9294d1d059f4b24f7849c2c46d0b",
  "url": "https://osv.dev/vulnerability/CVE-2026-98821",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "block: reject polled dio with user integrity metadata",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: block: reject polled dio with user integrity metadata IOCB_HAS_METADATA leaves iocb->private as a uio_meta, while iocb_bio_iopoll() expects a bio. Since 2729a60bbfb9, metadata I/O always uses __blkdev_direct_IO(), which never publishes the bio for polling, so IOPOLL calls bio_poll() on the uio_meta. Reproducer: io_uring IOPOLL plus a PI attribute on an integrity device (scsi_debug dif=1 dix=1). KASAN reports: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000004 KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027] RIP: 0010:bio_poll+0x9d/0x4b0 Call Trace: iocb_bio_iopoll+0x5b/0x80 io_uring_classic_poll+0xf3/0x140 io_do_iopoll+0x4e3/0xc00 io_iopoll_check+0x275/0x560 __do_sys_io_uring_enter+0x2e5/0x720 Return -EOPNOTSUPP when HIPRI is combined with user metadata.",
    "evidence": "osv:CVE-2026-98821",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.18.56",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.10",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-98821",
      "aliases": [
        "CVE-2026-98821"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "2729a60bbfb9215997f25372ebe9b7964f038296"
                },
                {
                  "fixed": "c97ef13ad96be0e08af38dfa2ed40cded0b53e1b"
                },
                {
                  "fixed": "dd33c03cefccdfcb223e9e6262643d64f8c1ae20"
                },
                {
                  "fixed": "2a42e6fe1293f2e2d579c9fe5bbab056dd8b880e"
                }
              ]
            },
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "6.16.8"
                },
                {
                  "fixed": "6.17"
                }
              ]
            },
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "17ecefc9fdd8c554e0d03e5a990daef19f930add"
                }
              ]
            }
          ],
          "versions": [
            "v6.16.12",
            "v6.16.11",
            "v6.16.10",
            "v6.16.9",
            "v6.16.8"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98821.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.17.0"
                },
                {
                  "fixed": "6.18.56"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.2.10"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98821.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:39.075163978Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/2a42e6fe1293f2e2d579c9fe5bbab056dd8b880e",
        "https://git.kernel.org/stable/c/c97ef13ad96be0e08af38dfa2ed40cded0b53e1b",
        "https://git.kernel.org/stable/c/dd33c03cefccdfcb223e9e6262643d64f8c1ae20",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98821.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-98821",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98821.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-98821",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 506758,
  "published_at": "2026-10-18T15:49:13.154+00:00"
}