CVE-2026-90170 (GCVE-0-2026-90170)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:06 – Updated: 2026-09-17 16:06
VLAI
Title
ksmbd: validate ipc response length before dereferencing its fields
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: validate ipc response length before dereferencing its fields ipc_validate_msg() computes the expected message size by reading length fields out of the response buffer supplied by the userspace ksmbd daemon (payload_sz, session_key_len, ngroups, ...). Those fields are read before the buffer is verified to be large enough to contain the struct they belong to, so a short response makes the read land past the end of the allocation. handle_response() sizes entry->response purely from the netlink attribute length (nla_len()) and only guards the leading handle read, so the daemon can install a response as small as the kmalloc-8 object seen below. When ipc_msg_send_request() then calls ipc_validate_msg() for a KSMBD_EVENT_RPC_REQUEST, the cast to struct ksmbd_rpc_command reads resp->payload_sz at offset 8 of an 8-byte allocation: [ 3697.841381] ================================================================== [ 3697.844099] BUG: KASAN: slab-out-of-bounds in ipc_msg_send_request+0x763/0x800 [ 3697.846604] Read of size 4 at addr ffff888105f95910 by task kworker/4:3/20682 [ 3697.849061] [ 3697.849801] CPU: 4 UID: 0 PID: 20682 Comm: kworker/4:3 Not tainted 7.2.0-rc3-next-20260717-virtme #117 PREEMPT(lazy) [ 3697.850077] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014 [ 3697.850303] Workqueue: ksmbd-io handle_ksmbd_work [ 3697.850592] Call Trace: [ 3697.850794] <TASK> [ 3697.850952] __dump_stack+0x21/0x60 [ 3697.851239] dump_stack_lvl+0xc2/0x100 [ 3697.851528] print_address_description+0x77/0x200 [ 3697.851816] ? ipc_msg_send_request+0x763/0x800 [ 3697.852024] print_report+0x58/0x70 [ 3697.852316] kasan_report+0x117/0x150 [ 3697.852585] ? down_write+0x146/0x1f0 [ 3697.852809] ? ipc_msg_send_request+0x763/0x800 [ 3697.853082] ipc_msg_send_request+0x763/0x800 [ 3697.853385] ? __pfx_ipc_msg_send_request+0x10/0x10 [ 3697.853604] ? kasan_unpoison+0x48/0x70 [ 3697.853936] ? __pfx___up_read+0x10/0x10 [ 3697.854221] ksmbd_rpc_ioctl+0x380/0x520 [ 3697.854542] ? __pfx_ksmbd_rpc_ioctl+0x10/0x10 [ 3697.854757] ? kasan_unpoison+0x48/0x70 [ 3697.854962] ? copy_from_kernel_nofault+0x32c/0x4e0 [ 3697.855166] ? kasan_unpoison+0x48/0x70 [ 3697.855416] fsctl_pipe_transceive+0x139/0x7a0 [ 3697.855705] ? __pfx_copy_from_kernel_nofault+0x10/0x10 [ 3697.855937] ? __pfx_fsctl_pipe_transceive+0x10/0x10 [ 3697.856388] ? __sanitizer_cov_trace_switch+0x7b/0x140 [ 3697.856620] smb2_ioctl+0x1141/0x3420 [ 3697.856994] ? __pfx_smb2_ioctl+0x10/0x10 [ 3697.857182] ? get_smb2_cmd_val+0xe3/0x1c0 [ 3697.857655] handle_ksmbd_work+0x9ad/0x15e0 [ 3697.858034] ? __pfx_handle_ksmbd_work+0x10/0x10 [ 3697.858251] ? lock_release+0xf7/0x360 [ 3697.858466] ? process_scheduled_works+0x954/0x1600 [ 3697.858698] ? process_scheduled_works+0x954/0x1600 [ 3697.858905] process_scheduled_works+0xc22/0x1600 [ 3697.859368] ? __pfx_process_scheduled_works+0x10/0x10 [ 3697.859637] ? __pfx_assign_work+0x10/0x10 [ 3697.859896] ? lock_is_held_type+0x7b/0x110 [ 3697.860146] worker_thread+0x975/0xee0 [ 3697.860524] ? __pfx_do_raw_spin_lock+0x10/0x10 [ 3697.860830] ? __kthread_parkme+0x21e/0x260 [ 3697.861105] kthread+0x3a6/0x490 [ 3697.861423] ? __pfx_worker_thread+0x10/0x10 [ 3697.861643] ? __pfx_kthread+0x10/0x10 [ 3697.861878] ret_from_fork+0x55a/0xa20 [ 3697.862194] ? __pfx_ret_from_fork+0x10/0x10 [ 3697.862480] ? __pfx_kthread+0x10/0x10 [ 3697.862714] ret_from_fork_asm+0x1a/0x30 [ 3697.862965] </TASK> [ 3697.863039] [ 3697.938882] Allocated by task 20761: [ 3697.940257] kasan_save_track+0x3e/0x80 [ 3697.941782] __kasan_kmalloc+0x72/0x90 [ 3697.943228] __kvmalloc_node_noprof+0x3e9/0x6a0 [ 3697.944948] handle_generic_event+0x59b/0x750 [ 3697.946592] genl_family_rcv_msg_doit+0x3d6/0x560 [ 3697.946977] genl_rcv_msg+0x67c/0x900 [ 3697.947224] netlink_rcv_skb+0x286/0x580 [ 3697.947488] genl_rcv+0x2d/0x80 [ 3 ---truncated---
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: bf396208418371174869baba9434535cd3288e80 , < 17b7d1a2b4d5473df5dca8c9a07d65021806c23a (git)
Affected: 7dd0c858e1909769a4c91842724315ee74f1a5f1 , < 398cba4b646a6c08ff3d79e6b1e70e5ddae8a065 (git)
Affected: 299db777ea0cfa5c407e41b045c24a14c034c27b , < 0aa8f94bfd4d818284c8a7ce0040d40ca1ec3595 (git)
Affected: d6a6aa81eac2c9bff66dc6e191179cb69a14426b , < c494fcf8e89e3c970e13d78ebe62bf5d8f2b1c52 (git)
Affected: d6a6aa81eac2c9bff66dc6e191179cb69a14426b , < e9b33376bd07bca4175f7bcc2d6034ef250f8181 (git)
Affected: 99c631d0366c1eab8fb188fe66425f4581ebdde4 (git)
Affected: 6.6.141 , < 6.6.157 (semver)
Affected: 6.12.84 , < 6.12.110 (semver)
Affected: 6.18.25 , < 6.18.52 (semver)
Affected: 7.0.2 , < 7.1 (semver)
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Linux Linux Affected: 7.1
Unaffected: 0 , < 7.1 (semver)
Unaffected: 6.6.157 , ≤ 6.6.* (semver)
Unaffected: 6.12.110 , ≤ 6.12.* (semver)
Unaffected: 6.18.52 , ≤ 6.18.* (semver)
Unaffected: 7.2.6 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/transport_ipc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "17b7d1a2b4d5473df5dca8c9a07d65021806c23a",
              "status": "affected",
              "version": "bf396208418371174869baba9434535cd3288e80",
              "versionType": "git"
            },
            {
              "lessThan": "398cba4b646a6c08ff3d79e6b1e70e5ddae8a065",
              "status": "affected",
              "version": "7dd0c858e1909769a4c91842724315ee74f1a5f1",
              "versionType": "git"
            },
            {
              "lessThan": "0aa8f94bfd4d818284c8a7ce0040d40ca1ec3595",
              "status": "affected",
              "version": "299db777ea0cfa5c407e41b045c24a14c034c27b",
              "versionType": "git"
            },
            {
              "lessThan": "c494fcf8e89e3c970e13d78ebe62bf5d8f2b1c52",
              "status": "affected",
              "version": "d6a6aa81eac2c9bff66dc6e191179cb69a14426b",
              "versionType": "git"
            },
            {
              "lessThan": "e9b33376bd07bca4175f7bcc2d6034ef250f8181",
              "status": "affected",
              "version": "d6a6aa81eac2c9bff66dc6e191179cb69a14426b",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "99c631d0366c1eab8fb188fe66425f4581ebdde4",
              "versionType": "git"
            },
            {
              "lessThan": "6.6.157",
              "status": "affected",
              "version": "6.6.141",
              "versionType": "semver"
            },
            {
              "lessThan": "6.12.110",
              "status": "affected",
              "version": "6.12.84",
              "versionType": "semver"
            },
            {
              "lessThan": "6.18.52",
              "status": "affected",
              "version": "6.18.25",
              "versionType": "semver"
            },
            {
              "lessThan": "7.1",
              "status": "affected",
              "version": "7.0.2",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/transport_ipc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.1"
            },
            {
              "lessThan": "7.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
                  "versionStartIncluding": "6.6.141",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.110",
                  "versionStartIncluding": "6.12.84",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.52",
                  "versionStartIncluding": "6.18.25",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "7.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "7.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "7.0.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: validate ipc response length before dereferencing its fields\n\nipc_validate_msg() computes the expected message size by reading length\nfields out of the response buffer supplied by the userspace ksmbd daemon\n(payload_sz, session_key_len, ngroups, ...).  Those fields are read before\nthe buffer is verified to be large enough to contain the struct they belong\nto, so a short response makes the read land past the end of the allocation.\n\nhandle_response() sizes entry-\u003eresponse purely from the netlink attribute\nlength (nla_len()) and only guards the leading handle read, so the daemon\ncan install a response as small as the kmalloc-8 object seen below.  When\nipc_msg_send_request() then calls ipc_validate_msg() for a\nKSMBD_EVENT_RPC_REQUEST, the cast to struct ksmbd_rpc_command reads\nresp-\u003epayload_sz at offset 8 of an 8-byte allocation:\n\n[ 3697.841381] ==================================================================\n[ 3697.844099] BUG: KASAN: slab-out-of-bounds in ipc_msg_send_request+0x763/0x800\n[ 3697.846604] Read of size 4 at addr ffff888105f95910 by task kworker/4:3/20682\n[ 3697.849061]\n[ 3697.849801] CPU: 4 UID: 0 PID: 20682 Comm: kworker/4:3 Not tainted 7.2.0-rc3-next-20260717-virtme #117 PREEMPT(lazy)\n[ 3697.850077] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014\n[ 3697.850303] Workqueue: ksmbd-io handle_ksmbd_work\n[ 3697.850592] Call Trace:\n[ 3697.850794]  \u003cTASK\u003e\n[ 3697.850952]  __dump_stack+0x21/0x60\n[ 3697.851239]  dump_stack_lvl+0xc2/0x100\n[ 3697.851528]  print_address_description+0x77/0x200\n[ 3697.851816]  ? ipc_msg_send_request+0x763/0x800\n[ 3697.852024]  print_report+0x58/0x70\n[ 3697.852316]  kasan_report+0x117/0x150\n[ 3697.852585]  ? down_write+0x146/0x1f0\n[ 3697.852809]  ? ipc_msg_send_request+0x763/0x800\n[ 3697.853082]  ipc_msg_send_request+0x763/0x800\n[ 3697.853385]  ? __pfx_ipc_msg_send_request+0x10/0x10\n[ 3697.853604]  ? kasan_unpoison+0x48/0x70\n[ 3697.853936]  ? __pfx___up_read+0x10/0x10\n[ 3697.854221]  ksmbd_rpc_ioctl+0x380/0x520\n[ 3697.854542]  ? __pfx_ksmbd_rpc_ioctl+0x10/0x10\n[ 3697.854757]  ? kasan_unpoison+0x48/0x70\n[ 3697.854962]  ? copy_from_kernel_nofault+0x32c/0x4e0\n[ 3697.855166]  ? kasan_unpoison+0x48/0x70\n[ 3697.855416]  fsctl_pipe_transceive+0x139/0x7a0\n[ 3697.855705]  ? __pfx_copy_from_kernel_nofault+0x10/0x10\n[ 3697.855937]  ? __pfx_fsctl_pipe_transceive+0x10/0x10\n[ 3697.856388]  ? __sanitizer_cov_trace_switch+0x7b/0x140\n[ 3697.856620]  smb2_ioctl+0x1141/0x3420\n[ 3697.856994]  ? __pfx_smb2_ioctl+0x10/0x10\n[ 3697.857182]  ? get_smb2_cmd_val+0xe3/0x1c0\n[ 3697.857655]  handle_ksmbd_work+0x9ad/0x15e0\n[ 3697.858034]  ? __pfx_handle_ksmbd_work+0x10/0x10\n[ 3697.858251]  ? lock_release+0xf7/0x360\n[ 3697.858466]  ? process_scheduled_works+0x954/0x1600\n[ 3697.858698]  ? process_scheduled_works+0x954/0x1600\n[ 3697.858905]  process_scheduled_works+0xc22/0x1600\n[ 3697.859368]  ? __pfx_process_scheduled_works+0x10/0x10\n[ 3697.859637]  ? __pfx_assign_work+0x10/0x10\n[ 3697.859896]  ? lock_is_held_type+0x7b/0x110\n[ 3697.860146]  worker_thread+0x975/0xee0\n[ 3697.860524]  ? __pfx_do_raw_spin_lock+0x10/0x10\n[ 3697.860830]  ? __kthread_parkme+0x21e/0x260\n[ 3697.861105]  kthread+0x3a6/0x490\n[ 3697.861423]  ? __pfx_worker_thread+0x10/0x10\n[ 3697.861643]  ? __pfx_kthread+0x10/0x10\n[ 3697.861878]  ret_from_fork+0x55a/0xa20\n[ 3697.862194]  ? __pfx_ret_from_fork+0x10/0x10\n[ 3697.862480]  ? __pfx_kthread+0x10/0x10\n[ 3697.862714]  ret_from_fork_asm+0x1a/0x30\n[ 3697.862965]  \u003c/TASK\u003e\n[ 3697.863039]\n[ 3697.938882] Allocated by task 20761:\n[ 3697.940257]  kasan_save_track+0x3e/0x80\n[ 3697.941782]  __kasan_kmalloc+0x72/0x90\n[ 3697.943228]  __kvmalloc_node_noprof+0x3e9/0x6a0\n[ 3697.944948]  handle_generic_event+0x59b/0x750\n[ 3697.946592]  genl_family_rcv_msg_doit+0x3d6/0x560\n[ 3697.946977]  genl_rcv_msg+0x67c/0x900\n[ 3697.947224]  netlink_rcv_skb+0x286/0x580\n[ 3697.947488]  genl_rcv+0x2d/0x80\n[ 3\n---truncated---"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-17T16:06:58.486Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/17b7d1a2b4d5473df5dca8c9a07d65021806c23a"
        },
        {
          "url": "https://git.kernel.org/stable/c/398cba4b646a6c08ff3d79e6b1e70e5ddae8a065"
        },
        {
          "url": "https://git.kernel.org/stable/c/0aa8f94bfd4d818284c8a7ce0040d40ca1ec3595"
        },
        {
          "url": "https://git.kernel.org/stable/c/c494fcf8e89e3c970e13d78ebe62bf5d8f2b1c52"
        },
        {
          "url": "https://git.kernel.org/stable/c/e9b33376bd07bca4175f7bcc2d6034ef250f8181"
        }
      ],
      "title": "ksmbd: validate ipc response length before dereferencing its fields",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90170",
    "datePublished": "2026-09-17T16:06:58.486Z",
    "dateReserved": "2026-09-11T19:38:34.790Z",
    "dateUpdated": "2026-09-17T16:06:58.486Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-90170",
      "date": "2026-09-25",
      "epss": "0.002",
      "percentile": "0.08758"
    },
    "microsoft_vex": {
      "current_release_date": "2026-09-24T01:57:10.000Z",
      "cve": "CVE-2026-90170",
      "id": "msrc_CVE-2026-90170",
      "initial_release_date": "2026-09-19T01:17:57.000Z",
      "product_status:fixed": "1",
      "product_status:known_affected": "2",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "ksmbd: validate ipc response length before dereferencing its fields",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-90170.json",
      "version": "4"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "fs/smb/server/transport_ipc.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "17b7d1a2b4d5473df5dca8c9a07d65021806c23a",
                    "status": "affected",
                    "version": "bf396208418371174869baba9434535cd3288e80",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "398cba4b646a6c08ff3d79e6b1e70e5ddae8a065",
                    "status": "affected",
                    "version": "7dd0c858e1909769a4c91842724315ee74f1a5f1",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "0aa8f94bfd4d818284c8a7ce0040d40ca1ec3595",
                    "status": "affected",
                    "version": "299db777ea0cfa5c407e41b045c24a14c034c27b",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "c494fcf8e89e3c970e13d78ebe62bf5d8f2b1c52",
                    "status": "affected",
                    "version": "d6a6aa81eac2c9bff66dc6e191179cb69a14426b",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "e9b33376bd07bca4175f7bcc2d6034ef250f8181",
                    "status": "affected",
                    "version": "d6a6aa81eac2c9bff66dc6e191179cb69a14426b",
                    "versionType": "git"
                  },
                  {
                    "status": "affected",
                    "version": "99c631d0366c1eab8fb188fe66425f4581ebdde4",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "6.6.157",
                    "status": "affected",
                    "version": "6.6.141",
                    "versionType": "semver"
                  },
                  {
                    "lessThan": "6.12.110",
                    "status": "affected",
                    "version": "6.12.84",
                    "versionType": "semver"
                  },
                  {
                    "lessThan": "6.18.52",
                    "status": "affected",
                    "version": "6.18.25",
                    "versionType": "semver"
                  },
                  {
                    "lessThan": "7.1",
                    "status": "affected",
                    "version": "7.0.2",
                    "versionType": "semver"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "fs/smb/server/transport_ipc.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "7.1"
                  },
                  {
                    "lessThan": "7.1",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.6.*",
                    "status": "unaffected",
                    "version": "6.6.157",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.12.*",
                    "status": "unaffected",
                    "version": "6.12.110",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.18.*",
                    "status": "unaffected",
                    "version": "6.18.52",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.2.*",
                    "status": "unaffected",
                    "version": "7.2.6",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "7.3-rc1",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: validate ipc response length before dereferencing its fields\n\nipc_validate_msg() computes the expected message size by reading length\nfields out of the response buffer supplied by the userspace ksmbd daemon\n(payload_sz, session_key_len, ngroups, ...).  Those fields are read before\nthe buffer is verified to be large enough to contain the struct they belong\nto, so a short response makes the read land past the end of the allocation.\n\nhandle_response() sizes entry-\u003eresponse purely from the netlink attribute\nlength (nla_len()) and only guards the leading handle read, so the daemon\ncan install a response as small as the kmalloc-8 object seen below.  When\nipc_msg_send_request() then calls ipc_validate_msg() for a\nKSMBD_EVENT_RPC_REQUEST, the cast to struct ksmbd_rpc_command reads\nresp-\u003epayload_sz at offset 8 of an 8-byte allocation:\n\n[ 3697.841381] ==================================================================\n[ 3697.844099] BUG: KASAN: slab-out-of-bounds in ipc_msg_send_request+0x763/0x800\n[ 3697.846604] Read of size 4 at addr ffff888105f95910 by task kworker/4:3/20682\n[ 3697.849061]\n[ 3697.849801] CPU: 4 UID: 0 PID: 20682 Comm: kworker/4:3 Not tainted 7.2.0-rc3-next-20260717-virtme #117 PREEMPT(lazy)\n[ 3697.850077] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014\n[ 3697.850303] Workqueue: ksmbd-io handle_ksmbd_work\n[ 3697.850592] Call Trace:\n[ 3697.850794]  \u003cTASK\u003e\n[ 3697.850952]  __dump_stack+0x21/0x60\n[ 3697.851239]  dump_stack_lvl+0xc2/0x100\n[ 3697.851528]  print_address_description+0x77/0x200\n[ 3697.851816]  ? ipc_msg_send_request+0x763/0x800\n[ 3697.852024]  print_report+0x58/0x70\n[ 3697.852316]  kasan_report+0x117/0x150\n[ 3697.852585]  ? down_write+0x146/0x1f0\n[ 3697.852809]  ? ipc_msg_send_request+0x763/0x800\n[ 3697.853082]  ipc_msg_send_request+0x763/0x800\n[ 3697.853385]  ? __pfx_ipc_msg_send_request+0x10/0x10\n[ 3697.853604]  ? kasan_unpoison+0x48/0x70\n[ 3697.853936]  ? __pfx___up_read+0x10/0x10\n[ 3697.854221]  ksmbd_rpc_ioctl+0x380/0x520\n[ 3697.854542]  ? __pfx_ksmbd_rpc_ioctl+0x10/0x10\n[ 3697.854757]  ? kasan_unpoison+0x48/0x70\n[ 3697.854962]  ? copy_from_kernel_nofault+0x32c/0x4e0\n[ 3697.855166]  ? kasan_unpoison+0x48/0x70\n[ 3697.855416]  fsctl_pipe_transceive+0x139/0x7a0\n[ 3697.855705]  ? __pfx_copy_from_kernel_nofault+0x10/0x10\n[ 3697.855937]  ? __pfx_fsctl_pipe_transceive+0x10/0x10\n[ 3697.856388]  ? __sanitizer_cov_trace_switch+0x7b/0x140\n[ 3697.856620]  smb2_ioctl+0x1141/0x3420\n[ 3697.856994]  ? __pfx_smb2_ioctl+0x10/0x10\n[ 3697.857182]  ? get_smb2_cmd_val+0xe3/0x1c0\n[ 3697.857655]  handle_ksmbd_work+0x9ad/0x15e0\n[ 3697.858034]  ? __pfx_handle_ksmbd_work+0x10/0x10\n[ 3697.858251]  ? lock_release+0xf7/0x360\n[ 3697.858466]  ? process_scheduled_works+0x954/0x1600\n[ 3697.858698]  ? process_scheduled_works+0x954/0x1600\n[ 3697.858905]  process_scheduled_works+0xc22/0x1600\n[ 3697.859368]  ? __pfx_process_scheduled_works+0x10/0x10\n[ 3697.859637]  ? __pfx_assign_work+0x10/0x10\n[ 3697.859896]  ? lock_is_held_type+0x7b/0x110\n[ 3697.860146]  worker_thread+0x975/0xee0\n[ 3697.860524]  ? __pfx_do_raw_spin_lock+0x10/0x10\n[ 3697.860830]  ? __kthread_parkme+0x21e/0x260\n[ 3697.861105]  kthread+0x3a6/0x490\n[ 3697.861423]  ? __pfx_worker_thread+0x10/0x10\n[ 3697.861643]  ? __pfx_kthread+0x10/0x10\n[ 3697.861878]  ret_from_fork+0x55a/0xa20\n[ 3697.862194]  ? __pfx_ret_from_fork+0x10/0x10\n[ 3697.862480]  ? __pfx_kthread+0x10/0x10\n[ 3697.862714]  ret_from_fork_asm+0x1a/0x30\n[ 3697.862965]  \u003c/TASK\u003e\n[ 3697.863039]\n[ 3697.938882] Allocated by task 20761:\n[ 3697.940257]  kasan_save_track+0x3e/0x80\n[ 3697.941782]  __kasan_kmalloc+0x72/0x90\n[ 3697.943228]  __kvmalloc_node_noprof+0x3e9/0x6a0\n[ 3697.944948]  handle_generic_event+0x59b/0x750\n[ 3697.946592]  genl_family_rcv_msg_doit+0x3d6/0x560\n[ 3697.946977]  genl_rcv_msg+0x67c/0x900\n[ 3697.947224]  netlink_rcv_skb+0x286/0x580\n[ 3697.947488]  genl_rcv+0x2d/0x80\n[ 3\n---truncated---"
          }
        ],
        "id": "CVE-2026-90170",
        "lastModified": "2026-09-17T17:17:10.467",
        "metrics": {},
        "published": "2026-09-17T17:17:10.467",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/0aa8f94bfd4d818284c8a7ce0040d40ca1ec3595"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/17b7d1a2b4d5473df5dca8c9a07d65021806c23a"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/398cba4b646a6c08ff3d79e6b1e70e5ddae8a065"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/c494fcf8e89e3c970e13d78ebe62bf5d8f2b1c52"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/e9b33376bd07bca4175f7bcc2d6034ef250f8181"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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