ksmbd: validate ipc response length before dereferencing its fields
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Fixed
No CVSS vector from any source. Fix status from CNA.
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---
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 6.6.141 to before 6.6.157; 6.12.84 to before 6.12.110; 6.18.25 to before 6.18.52; 6.1.191 to before 6.2; 7.0.2 to before 7.1 | 6.6.157, 6.12.110, 6.18.52, 6.2, 7.1 | Patch available | CNA |
| Linux | Linux | 7.1 and later | 6.6.157, 6.12.110, 6.18.52, 7.2.6, 7.3 | Patch available | CNA |
- Linux VendorLinux Affected 6.6.141 to before 6.6.157; 6.12.84 to before 6.12.110; 6.18.25 to before 6.18.52; 6.1.191 to before 6.2; 7.0.2 to before 7.1 Fixed in 6.6.157, 6.12.110, 6.18.52, 6.2, 7.1 Patch available CNA
- Linux VendorLinux Affected 7.1 and later Fixed in 6.6.157, 6.12.110, 6.18.52, 7.2.6, 7.3 Patch available CNA
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.6.157, 6.12.110, 6.18.52, 6.2, 7.1
- Fix · CNA Linux (Linux) Fixed in 6.6.157, 6.12.110, 6.18.52, 7.2.6, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 7 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Container Platform 5
Timeline
- 2026-10-02 Threatist record created from CVE-2026-90170
- 2026-10-03 Alias added: GHSA-7vg6-6285-wmrm
- 2026-10-13 Affected versions changed · Red Hat
- 2026-10-13 CVSS score added · Red Hat
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-30 Fix available: Linux/[email protected] · CNA
- 2026-11-06 Affected versions changed · Red Hat
References
Other 5
- 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
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- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
Sources
- CVE-2026-90170 · CVE Program
- CVE-2026-90170 · NVD
- FIRST EPSS
- GHSA-7vg6-6285-wmrm · GitHub Advisory Database · CC BY 4.0
- CVE-2026-90170 · Red Hat security data · CC BY 4.0
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