CVE-2026-98812 (GCVE-0-2026-98812)
Vulnerability from cvelistv5
Published
2026-10-18 15:48
Modified
2026-10-30 12:39
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: net/mctp: publish the mctp_dev only after it is initialised mctp_add_dev() links the new mctp_dev into dev->mctp_ptr before mdev->dev is assigned, so a reader that picks the device up in that window dereferences a net_device pointer that is still NULL: KASAN: null-ptr-deref in range [0x00000000000000b0-0x00000000000000b7] Call Trace: <TASK> ? __pfx_mctp_sendmsg (./include/linux/sockptr.h:49) ? __pfx_mctp_dst_output (net/mctp/route.c:41) ? selinux_socket_sendmsg (security/selinux/hooks.c:5278) ____sys_sendmsg (net/socket.c:775 (discriminator 1) net/socket.c:790 (discriminator 1) net/socket.c:2684 (discriminator 1)) ? __pfx_____sys_sendmsg (net/socket.c:1131) ? __pfx_copy_msghdr_from_user (net/socket.c:2590) ? update_cfs_rq_load_avg (kernel/sched/fair.c:5478) ___sys_sendmsg (net/socket.c:2738) ? __pfx____sys_sendmsg (net/socket.c:2625) ? perf_event_task_tick (./include/linux/rcupdate.h:838) ? sched_tick (kernel/sched/core.c:5818) ? clockevents_program_event (kernel/time/clockevents.c:372) ? fdget (./include/linux/rcupdate.h:873 fs/file.c:1100) __sys_sendmsg (net/socket.c:2770) ? __pfx___sys_sendmsg (net/socket.c:2751) do_syscall_64 (arch/x86/entry/syscall_64.c:63) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) </TASK> Fix by publishing only once the object is fully initialised: __mctp_dev_get() runs under rcu_read_lock() only and hands this object to readers as soon as mctp_ptr is assigned, so they must never observe mdev->dev == NULL.
References
Impacted products
Vendor Product Version
Linux Linux Version: 583be982d93479ea3d85091b0fd0b01201ede87d
Version: 583be982d93479ea3d85091b0fd0b01201ede87d
Version: 583be982d93479ea3d85091b0fd0b01201ede87d
Version: 583be982d93479ea3d85091b0fd0b01201ede87d
Version: 583be982d93479ea3d85091b0fd0b01201ede87d
Version: 583be982d93479ea3d85091b0fd0b01201ede87d
Version: 583be982d93479ea3d85091b0fd0b01201ede87d
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/mctp/device.c"
          ],
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          "vendor": "Linux",
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        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "5.15"
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              "version": "5.15.224",
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              "version": "6.6.160",
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            },
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              "lessThanOrEqual": "6.12.*",
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              "version": "6.12.113",
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            },
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              "lessThanOrEqual": "6.18.*",
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              "version": "6.18.56",
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            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.10",
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            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                {
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                }
              ],
              "negate": false,
              "operator": "OR"
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          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mctp: publish the mctp_dev only after it is initialised\n\nmctp_add_dev() links the new mctp_dev into dev-\u003emctp_ptr before mdev-\u003edev\nis assigned, so a reader that picks the device up in that window\ndereferences a net_device pointer that is still NULL:\n\nKASAN: null-ptr-deref in range [0x00000000000000b0-0x00000000000000b7]\nCall Trace:\n \u003cTASK\u003e\n ? __pfx_mctp_sendmsg (./include/linux/sockptr.h:49)\n ? __pfx_mctp_dst_output (net/mctp/route.c:41)\n ? selinux_socket_sendmsg (security/selinux/hooks.c:5278)\n ____sys_sendmsg (net/socket.c:775 (discriminator 1) net/socket.c:790\n (discriminator 1) net/socket.c:2684 (discriminator 1))\n ? __pfx_____sys_sendmsg (net/socket.c:1131)\n ? __pfx_copy_msghdr_from_user (net/socket.c:2590)\n ? update_cfs_rq_load_avg (kernel/sched/fair.c:5478)\n ___sys_sendmsg (net/socket.c:2738)\n ? __pfx____sys_sendmsg (net/socket.c:2625)\n ? perf_event_task_tick (./include/linux/rcupdate.h:838)\n ? sched_tick (kernel/sched/core.c:5818)\n ? clockevents_program_event (kernel/time/clockevents.c:372)\n ? fdget (./include/linux/rcupdate.h:873 fs/file.c:1100)\n __sys_sendmsg (net/socket.c:2770)\n ? __pfx___sys_sendmsg (net/socket.c:2751)\n do_syscall_64 (arch/x86/entry/syscall_64.c:63)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n \u003c/TASK\u003e\n\nFix by publishing only once the object is fully initialised:\n__mctp_dev_get() runs under rcu_read_lock() only and hands\nthis object to readers as soon as mctp_ptr is assigned, so\nthey must never observe mdev-\u003edev == NULL."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-30T12:39:58.094Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/58a270b5ecd8629114a4754d642bad6a33bef493"
        },
        {
          "url": "https://git.kernel.org/stable/c/fdf09d0fa2fb639950bede185d22689f68df140e"
        },
        {
          "url": "https://git.kernel.org/stable/c/288ef37e0c463192dbb6436e61cdc07ce666dcb9"
        },
        {
          "url": "https://git.kernel.org/stable/c/af6e4f931afc2d670d133aa2bedc8b6e3753c618"
        },
        {
          "url": "https://git.kernel.org/stable/c/63120572edde85bb2b70b0ed4d4817ed52247613"
        },
        {
          "url": "https://git.kernel.org/stable/c/f37f42e6e039a48c2dcf6c079b9f7fbc864ab7ef"
        },
        {
          "url": "https://git.kernel.org/stable/c/aadf655e8ea9a8ffa24bb8d69f504572e8d18181"
        }
      ],
      "title": "net/mctp: publish the mctp_dev only after it is initialised",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98812",
    "datePublished": "2026-10-18T15:48:58.470Z",
    "dateReserved": "2026-09-25T10:25:14.371Z",
    "dateUpdated": "2026-10-30T12:39:58.094Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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