{"id":"CVE-2026-90170","state":"PUBLISHED","title":"ksmbd: validate ipc response length before dereferencing its fields","description":"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->response 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->payload_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]  <TASK>\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]  </TASK>\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---","publishedAt":"2026-09-17T16:06:58.486Z","updatedAt":"2026-10-30T12:34:35.628Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"bf396208418371174869baba9434535cd3288e80","status":"affected","lessThan":"17b7d1a2b4d5473df5dca8c9a07d65021806c23a","versionType":"git"},{"version":"7dd0c858e1909769a4c91842724315ee74f1a5f1","status":"affected","lessThan":"398cba4b646a6c08ff3d79e6b1e70e5ddae8a065","versionType":"git"},{"version":"299db777ea0cfa5c407e41b045c24a14c034c27b","status":"affected","lessThan":"0aa8f94bfd4d818284c8a7ce0040d40ca1ec3595","versionType":"git"},{"version":"d6a6aa81eac2c9bff66dc6e191179cb69a14426b","status":"affected","lessThan":"c494fcf8e89e3c970e13d78ebe62bf5d8f2b1c52","versionType":"git"},{"version":"d6a6aa81eac2c9bff66dc6e191179cb69a14426b","status":"affected","lessThan":"e9b33376bd07bca4175f7bcc2d6034ef250f8181","versionType":"git"},{"version":"52518503a1a00bc33e9522c4eb05df023e3ae978","status":"affected","versionType":"git"},{"version":"99c631d0366c1eab8fb188fe66425f4581ebdde4","status":"affected","versionType":"git"},{"version":"6.6.141","status":"affected","lessThan":"6.6.157","versionType":"semver"},{"version":"6.12.84","status":"affected","lessThan":"6.12.110","versionType":"semver"},{"version":"6.18.25","status":"affected","lessThan":"6.18.52","versionType":"semver"},{"version":"6.1.191","status":"affected","lessThan":"6.2","versionType":"semver"},{"version":"7.0.2","status":"affected","lessThan":"7.1","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/transport_ipc.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.1","versionType":"semver"},{"version":"6.6.157","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/transport_ipc.c"]}],"references":["https://git.kernel.org/stable/c/17b7d1a2b4d5473df5dca8c9a07d65021806c23a","https://git.kernel.org/stable/c/398cba4b646a6c08ff3d79e6b1e70e5ddae8a065","https://git.kernel.org/stable/c/0aa8f94bfd4d818284c8a7ce0040d40ca1ec3595","https://git.kernel.org/stable/c/c494fcf8e89e3c970e13d78ebe62bf5d8f2b1c52","https://git.kernel.org/stable/c/e9b33376bd07bca4175f7bcc2d6034ef250f8181"],"weaknesses":[],"ingestedAt":"2026-10-30T12:54:04.478Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/90xxx/CVE-2026-90170.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90170","state":"PUBLISHED","datePublished":"2026-09-17T16:06:58.486Z","dateUpdated":"2026-10-30T12:34:35.628Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.790Z"},"containers":{"cna":{"title":"ksmbd: validate ipc response length before dereferencing its fields","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->response 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->payload_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]  <TASK>\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]  </TASK>\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---"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"bf396208418371174869baba9434535cd3288e80","status":"affected","lessThan":"17b7d1a2b4d5473df5dca8c9a07d65021806c23a","versionType":"git"},{"version":"7dd0c858e1909769a4c91842724315ee74f1a5f1","status":"affected","lessThan":"398cba4b646a6c08ff3d79e6b1e70e5ddae8a065","versionType":"git"},{"version":"299db777ea0cfa5c407e41b045c24a14c034c27b","status":"affected","lessThan":"0aa8f94bfd4d818284c8a7ce0040d40ca1ec3595","versionType":"git"},{"version":"d6a6aa81eac2c9bff66dc6e191179cb69a14426b","status":"affected","lessThan":"c494fcf8e89e3c970e13d78ebe62bf5d8f2b1c52","versionType":"git"},{"version":"d6a6aa81eac2c9bff66dc6e191179cb69a14426b","status":"affected","lessThan":"e9b33376bd07bca4175f7bcc2d6034ef250f8181","versionType":"git"},{"version":"52518503a1a00bc33e9522c4eb05df023e3ae978","status":"affected","versionType":"git"},{"version":"99c631d0366c1eab8fb188fe66425f4581ebdde4","status":"affected","versionType":"git"},{"version":"6.6.141","status":"affected","lessThan":"6.6.157","versionType":"semver"},{"version":"6.12.84","status":"affected","lessThan":"6.12.110","versionType":"semver"},{"version":"6.18.25","status":"affected","lessThan":"6.18.52","versionType":"semver"},{"version":"6.1.191","status":"affected","lessThan":"6.2","versionType":"semver"},{"version":"7.0.2","status":"affected","lessThan":"7.1","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/transport_ipc.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.1","versionType":"semver"},{"version":"6.6.157","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/transport_ipc.c"]}],"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"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:34:35.628Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.141","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.84","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18.25","versionEndExcluding":"6.18.52"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}