Description
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix slab-out-of-bounds read in ksmbd_alloc_user()
ksmbd_alloc_user() copies resp->hash_sz bytes out of the mountd IPC
login response with
user->passkey_sz = resp->hash_sz;
user->passkey = kmalloc(resp->hash_sz, KSMBD_DEFAULT_GFP);
if (user->passkey)
memcpy(user->passkey, resp->hash, resp->hash_sz);
resp->hash_sz is a __u16 supplied by the response, but resp->hash[] is
only KSMBD_REQ_MAX_HASH_SZ bytes. A malformed or malicious login
response can set hash_sz well beyond that (up to 65535), so the memcpy()
reads past the end of the response object. ipc_validate_msg() does not
bound hash_sz, so reject any response whose hash_sz exceeds the on-stack
hash[] buffer before allocating and copying.
[ 2030.238706] BUG: KASAN: slab-out-of-bounds in ksmbd_alloc_user+0x278/0x680
[ 2030.240549] Read of size 65535 at addr ffff888121bb6680 by task kworker/4:1/18611
[ 2030.242296]
[ 2030.242710] CPU: 4 UID: 0 PID: 18611 Comm: kworker/4:1 Not tainted 7.1.0-next-20260623-virtme #96 PREEMPT(lazy)
[ 2030.242732] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
[ 2030.242743] Workqueue: ksmbd-io handle_ksmbd_work
[ 2030.242763] Call Trace:
[ 2030.242769] <TASK>
[ 2030.242776] dump_stack_lvl+0xa2/0xd0
[ 2030.242794] print_address_description+0x77/0x200
[ 2030.242815] ? ksmbd_alloc_user+0x278/0x680
[ 2030.242831] print_report+0x58/0x70
[ 2030.242848] kasan_report+0x117/0x150
[ 2030.242869] ? ksmbd_alloc_user+0x278/0x680
[ 2030.242888] kasan_check_range+0x3c7/0x3f0
[ 2030.242908] ? ksmbd_alloc_user+0x278/0x680
[ 2030.242925] __asan_memcpy+0x29/0x70
[ 2030.242942] ksmbd_alloc_user+0x278/0x680
[ 2030.242960] ksmbd_login_user+0xc3/0x120
[ 2030.242978] ntlm_authenticate+0x5e6/0x1b00
[ 2030.243017] ? __pfx_ntlm_authenticate+0x10/0x10
[ 2030.243035] ? ksmbd_session_lookup+0x188/0x1d0
[ 2030.243054] ? __pfx_ksmbd_session_lookup+0x10/0x10
[ 2030.243090] ? __sanitizer_cov_trace_switch+0x7b/0x140
[ 2030.243108] smb2_sess_setup+0x1e4a/0x27b0
[ 2030.243126] ? copy_from_kernel_nofault+0x199/0x300
[ 2030.243156] ? __pfx_smb2_sess_setup+0x10/0x10
[ 2030.243173] ? get_smb2_cmd_val+0xe3/0x1c0
[ 2030.243208] handle_ksmbd_work+0x954/0x1280
[ 2030.243230] ? __pfx_handle_ksmbd_work+0x10/0x10
[ 2030.243249] ? process_scheduled_works+0xa07/0x1490
[ 2030.243270] ? process_scheduled_works+0xa07/0x1490
[ 2030.243291] process_scheduled_works+0xa70/0x1490
[ 2030.243320] ? __pfx_process_scheduled_works+0x10/0x10
[ 2030.243340] ? do_raw_spin_lock+0x130/0x300
[ 2030.243358] ? lock_is_held_type+0x7b/0x110
[ 2030.243388] worker_thread+0x932/0xe20
[ 2030.243415] kthread+0x38a/0x470
[ 2030.243431] ? __pfx_worker_thread+0x10/0x10
[ 2030.243451] ? __pfx_kthread+0x10/0x10
[ 2030.243467] ret_from_fork+0x484/0x910
[ 2030.243485] ? __pfx_ret_from_fork+0x10/0x10
[ 2030.243501] ? __switch_to+0xc77/0x12c0
[ 2030.243523] ? __pfx_kthread+0x10/0x10
[ 2030.243540] ret_from_fork_asm+0x1a/0x30
[ 2030.243564] </TASK>
[ 2030.243570]
[ 2030.290164] Allocated by task 19279:
[ 2030.290911] kasan_save_track+0x3e/0x80
[ 2030.292179] __kasan_kmalloc+0x72/0x90
[ 2030.293217] __kvmalloc_node_noprof+0x3ff/0x6b0
[ 2030.294467] handle_generic_event+0x59b/0x750
[ 2030.295345] genl_family_rcv_msg_doit+0x238/0x340
[ 2030.296553] genl_rcv_msg+0x606/0x7b0
[ 2030.297129] netlink_rcv_skb+0x22b/0x4a0
[ 2030.298500] genl_rcv+0x2d/0x40
[ 2030.299273] netlink_unicast+0x7ba/0x930
[ 2030.300019] netlink_sendmsg+0x8c3/0xb00
[ 2030.301073] __sock_sendmsg+0xec/0x140
[ 2030.301579] __sys_sendto+0x357/0x470
[ 2030.302255] __x64_sys_sendto+0xe3/0x100
[ 2030.303425] do_syscall_64+0x135/0x460
[ 2030.304763] entry_SYSCALL_64_after_hwframe+0x77/0x7f
[ 2030.305594]
[ 2030.305819] The buggy address belongs to the object at ffff888121bb6640
[ 2030.305819] which belongs to the cache kmalloc-192 of size 192
[ 2030.309595] The buggy address
---truncated---
ksmbd: fix slab-out-of-bounds read in ksmbd_alloc_user()
ksmbd_alloc_user() copies resp->hash_sz bytes out of the mountd IPC
login response with
user->passkey_sz = resp->hash_sz;
user->passkey = kmalloc(resp->hash_sz, KSMBD_DEFAULT_GFP);
if (user->passkey)
memcpy(user->passkey, resp->hash, resp->hash_sz);
resp->hash_sz is a __u16 supplied by the response, but resp->hash[] is
only KSMBD_REQ_MAX_HASH_SZ bytes. A malformed or malicious login
response can set hash_sz well beyond that (up to 65535), so the memcpy()
reads past the end of the response object. ipc_validate_msg() does not
bound hash_sz, so reject any response whose hash_sz exceeds the on-stack
hash[] buffer before allocating and copying.
[ 2030.238706] BUG: KASAN: slab-out-of-bounds in ksmbd_alloc_user+0x278/0x680
[ 2030.240549] Read of size 65535 at addr ffff888121bb6680 by task kworker/4:1/18611
[ 2030.242296]
[ 2030.242710] CPU: 4 UID: 0 PID: 18611 Comm: kworker/4:1 Not tainted 7.1.0-next-20260623-virtme #96 PREEMPT(lazy)
[ 2030.242732] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
[ 2030.242743] Workqueue: ksmbd-io handle_ksmbd_work
[ 2030.242763] Call Trace:
[ 2030.242769] <TASK>
[ 2030.242776] dump_stack_lvl+0xa2/0xd0
[ 2030.242794] print_address_description+0x77/0x200
[ 2030.242815] ? ksmbd_alloc_user+0x278/0x680
[ 2030.242831] print_report+0x58/0x70
[ 2030.242848] kasan_report+0x117/0x150
[ 2030.242869] ? ksmbd_alloc_user+0x278/0x680
[ 2030.242888] kasan_check_range+0x3c7/0x3f0
[ 2030.242908] ? ksmbd_alloc_user+0x278/0x680
[ 2030.242925] __asan_memcpy+0x29/0x70
[ 2030.242942] ksmbd_alloc_user+0x278/0x680
[ 2030.242960] ksmbd_login_user+0xc3/0x120
[ 2030.242978] ntlm_authenticate+0x5e6/0x1b00
[ 2030.243017] ? __pfx_ntlm_authenticate+0x10/0x10
[ 2030.243035] ? ksmbd_session_lookup+0x188/0x1d0
[ 2030.243054] ? __pfx_ksmbd_session_lookup+0x10/0x10
[ 2030.243090] ? __sanitizer_cov_trace_switch+0x7b/0x140
[ 2030.243108] smb2_sess_setup+0x1e4a/0x27b0
[ 2030.243126] ? copy_from_kernel_nofault+0x199/0x300
[ 2030.243156] ? __pfx_smb2_sess_setup+0x10/0x10
[ 2030.243173] ? get_smb2_cmd_val+0xe3/0x1c0
[ 2030.243208] handle_ksmbd_work+0x954/0x1280
[ 2030.243230] ? __pfx_handle_ksmbd_work+0x10/0x10
[ 2030.243249] ? process_scheduled_works+0xa07/0x1490
[ 2030.243270] ? process_scheduled_works+0xa07/0x1490
[ 2030.243291] process_scheduled_works+0xa70/0x1490
[ 2030.243320] ? __pfx_process_scheduled_works+0x10/0x10
[ 2030.243340] ? do_raw_spin_lock+0x130/0x300
[ 2030.243358] ? lock_is_held_type+0x7b/0x110
[ 2030.243388] worker_thread+0x932/0xe20
[ 2030.243415] kthread+0x38a/0x470
[ 2030.243431] ? __pfx_worker_thread+0x10/0x10
[ 2030.243451] ? __pfx_kthread+0x10/0x10
[ 2030.243467] ret_from_fork+0x484/0x910
[ 2030.243485] ? __pfx_ret_from_fork+0x10/0x10
[ 2030.243501] ? __switch_to+0xc77/0x12c0
[ 2030.243523] ? __pfx_kthread+0x10/0x10
[ 2030.243540] ret_from_fork_asm+0x1a/0x30
[ 2030.243564] </TASK>
[ 2030.243570]
[ 2030.290164] Allocated by task 19279:
[ 2030.290911] kasan_save_track+0x3e/0x80
[ 2030.292179] __kasan_kmalloc+0x72/0x90
[ 2030.293217] __kvmalloc_node_noprof+0x3ff/0x6b0
[ 2030.294467] handle_generic_event+0x59b/0x750
[ 2030.295345] genl_family_rcv_msg_doit+0x238/0x340
[ 2030.296553] genl_rcv_msg+0x606/0x7b0
[ 2030.297129] netlink_rcv_skb+0x22b/0x4a0
[ 2030.298500] genl_rcv+0x2d/0x40
[ 2030.299273] netlink_unicast+0x7ba/0x930
[ 2030.300019] netlink_sendmsg+0x8c3/0xb00
[ 2030.301073] __sock_sendmsg+0xec/0x140
[ 2030.301579] __sys_sendto+0x357/0x470
[ 2030.302255] __x64_sys_sendto+0xe3/0x100
[ 2030.303425] do_syscall_64+0x135/0x460
[ 2030.304763] entry_SYSCALL_64_after_hwframe+0x77/0x7f
[ 2030.305594]
[ 2030.305819] The buggy address belongs to the object at ffff888121bb6640
[ 2030.305819] which belongs to the cache kmalloc-192 of size 192
[ 2030.309595] The buggy address
---truncated---
Published:
2026-09-17
Score:
n/a
EPSS:
n/a
KEV:
No
Impact:
n/a
Action:
n/a
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
|||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
No data available yet.
Remediation
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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Advisories
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References
History
Thu, 17 Sep 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix slab-out-of-bounds read in ksmbd_alloc_user() ksmbd_alloc_user() copies resp->hash_sz bytes out of the mountd IPC login response with user->passkey_sz = resp->hash_sz; user->passkey = kmalloc(resp->hash_sz, KSMBD_DEFAULT_GFP); if (user->passkey) memcpy(user->passkey, resp->hash, resp->hash_sz); resp->hash_sz is a __u16 supplied by the response, but resp->hash[] is only KSMBD_REQ_MAX_HASH_SZ bytes. A malformed or malicious login response can set hash_sz well beyond that (up to 65535), so the memcpy() reads past the end of the response object. ipc_validate_msg() does not bound hash_sz, so reject any response whose hash_sz exceeds the on-stack hash[] buffer before allocating and copying. [ 2030.238706] BUG: KASAN: slab-out-of-bounds in ksmbd_alloc_user+0x278/0x680 [ 2030.240549] Read of size 65535 at addr ffff888121bb6680 by task kworker/4:1/18611 [ 2030.242296] [ 2030.242710] CPU: 4 UID: 0 PID: 18611 Comm: kworker/4:1 Not tainted 7.1.0-next-20260623-virtme #96 PREEMPT(lazy) [ 2030.242732] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014 [ 2030.242743] Workqueue: ksmbd-io handle_ksmbd_work [ 2030.242763] Call Trace: [ 2030.242769] <TASK> [ 2030.242776] dump_stack_lvl+0xa2/0xd0 [ 2030.242794] print_address_description+0x77/0x200 [ 2030.242815] ? ksmbd_alloc_user+0x278/0x680 [ 2030.242831] print_report+0x58/0x70 [ 2030.242848] kasan_report+0x117/0x150 [ 2030.242869] ? ksmbd_alloc_user+0x278/0x680 [ 2030.242888] kasan_check_range+0x3c7/0x3f0 [ 2030.242908] ? ksmbd_alloc_user+0x278/0x680 [ 2030.242925] __asan_memcpy+0x29/0x70 [ 2030.242942] ksmbd_alloc_user+0x278/0x680 [ 2030.242960] ksmbd_login_user+0xc3/0x120 [ 2030.242978] ntlm_authenticate+0x5e6/0x1b00 [ 2030.243017] ? __pfx_ntlm_authenticate+0x10/0x10 [ 2030.243035] ? ksmbd_session_lookup+0x188/0x1d0 [ 2030.243054] ? __pfx_ksmbd_session_lookup+0x10/0x10 [ 2030.243090] ? __sanitizer_cov_trace_switch+0x7b/0x140 [ 2030.243108] smb2_sess_setup+0x1e4a/0x27b0 [ 2030.243126] ? copy_from_kernel_nofault+0x199/0x300 [ 2030.243156] ? __pfx_smb2_sess_setup+0x10/0x10 [ 2030.243173] ? get_smb2_cmd_val+0xe3/0x1c0 [ 2030.243208] handle_ksmbd_work+0x954/0x1280 [ 2030.243230] ? __pfx_handle_ksmbd_work+0x10/0x10 [ 2030.243249] ? process_scheduled_works+0xa07/0x1490 [ 2030.243270] ? process_scheduled_works+0xa07/0x1490 [ 2030.243291] process_scheduled_works+0xa70/0x1490 [ 2030.243320] ? __pfx_process_scheduled_works+0x10/0x10 [ 2030.243340] ? do_raw_spin_lock+0x130/0x300 [ 2030.243358] ? lock_is_held_type+0x7b/0x110 [ 2030.243388] worker_thread+0x932/0xe20 [ 2030.243415] kthread+0x38a/0x470 [ 2030.243431] ? __pfx_worker_thread+0x10/0x10 [ 2030.243451] ? __pfx_kthread+0x10/0x10 [ 2030.243467] ret_from_fork+0x484/0x910 [ 2030.243485] ? __pfx_ret_from_fork+0x10/0x10 [ 2030.243501] ? __switch_to+0xc77/0x12c0 [ 2030.243523] ? __pfx_kthread+0x10/0x10 [ 2030.243540] ret_from_fork_asm+0x1a/0x30 [ 2030.243564] </TASK> [ 2030.243570] [ 2030.290164] Allocated by task 19279: [ 2030.290911] kasan_save_track+0x3e/0x80 [ 2030.292179] __kasan_kmalloc+0x72/0x90 [ 2030.293217] __kvmalloc_node_noprof+0x3ff/0x6b0 [ 2030.294467] handle_generic_event+0x59b/0x750 [ 2030.295345] genl_family_rcv_msg_doit+0x238/0x340 [ 2030.296553] genl_rcv_msg+0x606/0x7b0 [ 2030.297129] netlink_rcv_skb+0x22b/0x4a0 [ 2030.298500] genl_rcv+0x2d/0x40 [ 2030.299273] netlink_unicast+0x7ba/0x930 [ 2030.300019] netlink_sendmsg+0x8c3/0xb00 [ 2030.301073] __sock_sendmsg+0xec/0x140 [ 2030.301579] __sys_sendto+0x357/0x470 [ 2030.302255] __x64_sys_sendto+0xe3/0x100 [ 2030.303425] do_syscall_64+0x135/0x460 [ 2030.304763] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 2030.305594] [ 2030.305819] The buggy address belongs to the object at ffff888121bb6640 [ 2030.305819] which belongs to the cache kmalloc-192 of size 192 [ 2030.309595] The buggy address ---truncated--- | |
| Title | ksmbd: fix slab-out-of-bounds read in ksmbd_alloc_user() | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-17T16:07:01.106Z
Reserved: 2026-09-11T19:38:34.791Z
Link: CVE-2026-90174
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-17T17:17:11.083
Modified: 2026-09-17T17:17:11.083
Link: CVE-2026-90174
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.