ksmbd: validate ipc response length before dereferencing its fields

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-90170
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-17 17:17:10 UTC
Updated2026-09-17 17:17:10 UTC
DescriptionIn 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---

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected bf396208418371174869baba9434535cd3288e80 17b7d1a2b4d5473df5dca8c9a07d65021806c23a git Not specified
CNA Linux Linux affected 7dd0c858e1909769a4c91842724315ee74f1a5f1 398cba4b646a6c08ff3d79e6b1e70e5ddae8a065 git Not specified
CNA Linux Linux affected 299db777ea0cfa5c407e41b045c24a14c034c27b 0aa8f94bfd4d818284c8a7ce0040d40ca1ec3595 git Not specified
CNA Linux Linux affected d6a6aa81eac2c9bff66dc6e191179cb69a14426b c494fcf8e89e3c970e13d78ebe62bf5d8f2b1c52 git Not specified
CNA Linux Linux affected d6a6aa81eac2c9bff66dc6e191179cb69a14426b e9b33376bd07bca4175f7bcc2d6034ef250f8181 git Not specified
CNA Linux Linux affected 99c631d0366c1eab8fb188fe66425f4581ebdde4 git Not specified
CNA Linux Linux affected 6.6.141 6.6.157 semver Not specified
CNA Linux Linux affected 6.12.84 6.12.110 semver Not specified
CNA Linux Linux affected 6.18.25 6.18.52 semver Not specified
CNA Linux Linux affected 7.0.2 7.1 semver Not specified
CNA Linux Linux affected 7.1 Not specified
CNA Linux Linux unaffected 7.1 semver Not specified
CNA Linux Linux unaffected 6.6.157 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.110 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.52 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.6 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/398cba4b646a6c08ff3d79e6b1e70e5ddae8a065 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/0aa8f94bfd4d818284c8a7ce0040d40ca1ec3595 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c494fcf8e89e3c970e13d78ebe62bf5d8f2b1c52 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/e9b33376bd07bca4175f7bcc2d6034ef250f8181 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/17b7d1a2b4d5473df5dca8c9a07d65021806c23a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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