In the Linux kernel, the following vulnerability has been resolved:
net/mctp: publish the mctp_dev only after it is initialised
mctp_add_dev() links the new mctp_dev into dev->mctp_ptr before mdev->dev
is assigned, so a reader that picks the device up in that window
dereferences a net_device pointer that is still NULL:
KASAN: null-ptr-deref in range [0x00000000000000b0-0x00000000000000b7]
Call Trace:
<TASK>
? __pfx_mctp_sendmsg (./include/linux/sockptr.h:49)
? __pfx_mctp_dst_output (net/mctp/route.c:41)
? selinux_socket_sendmsg (security/selinux/hooks.c:5278)
____sys_sendmsg (net/socket.c:775 (discriminator 1) net/socket.c:790
(discriminator 1) net/socket.c:2684 (discriminator 1))
? __pfx_____sys_sendmsg (net/socket.c:1131)
? __pfx_copy_msghdr_from_user (net/socket.c:2590)
? update_cfs_rq_load_avg (kernel/sched/fair.c:5478)
___sys_sendmsg (net/socket.c:2738)
? __pfx____sys_sendmsg (net/socket.c:2625)
? perf_event_task_tick (./include/linux/rcupdate.h:838)
? sched_tick (kernel/sched/core.c:5818)
? clockevents_program_event (kernel/time/clockevents.c:372)
? fdget (./include/linux/rcupdate.h:873 fs/file.c:1100)
__sys_sendmsg (net/socket.c:2770)
? __pfx___sys_sendmsg (net/socket.c:2751)
do_syscall_64 (arch/x86/entry/syscall_64.c:63)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
</TASK>
Fix by publishing only once the object is fully initialised:
__mctp_dev_get() runs under rcu_read_lock() only and hands
this object to readers as soon as mctp_ptr is assigned, so
they must never observe mdev->dev == NULL.
net/mctp: publish the mctp_dev only after it is initialised
mctp_add_dev() links the new mctp_dev into dev->mctp_ptr before mdev->dev
is assigned, so a reader that picks the device up in that window
dereferences a net_device pointer that is still NULL:
KASAN: null-ptr-deref in range [0x00000000000000b0-0x00000000000000b7]
Call Trace:
<TASK>
? __pfx_mctp_sendmsg (./include/linux/sockptr.h:49)
? __pfx_mctp_dst_output (net/mctp/route.c:41)
? selinux_socket_sendmsg (security/selinux/hooks.c:5278)
____sys_sendmsg (net/socket.c:775 (discriminator 1) net/socket.c:790
(discriminator 1) net/socket.c:2684 (discriminator 1))
? __pfx_____sys_sendmsg (net/socket.c:1131)
? __pfx_copy_msghdr_from_user (net/socket.c:2590)
? update_cfs_rq_load_avg (kernel/sched/fair.c:5478)
___sys_sendmsg (net/socket.c:2738)
? __pfx____sys_sendmsg (net/socket.c:2625)
? perf_event_task_tick (./include/linux/rcupdate.h:838)
? sched_tick (kernel/sched/core.c:5818)
? clockevents_program_event (kernel/time/clockevents.c:372)
? fdget (./include/linux/rcupdate.h:873 fs/file.c:1100)
__sys_sendmsg (net/socket.c:2770)
? __pfx___sys_sendmsg (net/socket.c:2751)
do_syscall_64 (arch/x86/entry/syscall_64.c:63)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
</TASK>
Fix by publishing only once the object is fully initialised:
__mctp_dev_get() runs under rcu_read_lock() only and hands
this object to readers as soon as mctp_ptr is assigned, so
they must never observe mdev->dev == NULL.
Metrics
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Fixes
Solution
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Workaround
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References
History
Sun, 18 Oct 2026 20:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-367 CWE-476 |
Sun, 18 Oct 2026 16:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: net/mctp: publish the mctp_dev only after it is initialised mctp_add_dev() links the new mctp_dev into dev->mctp_ptr before mdev->dev is assigned, so a reader that picks the device up in that window dereferences a net_device pointer that is still NULL: KASAN: null-ptr-deref in range [0x00000000000000b0-0x00000000000000b7] Call Trace: <TASK> ? __pfx_mctp_sendmsg (./include/linux/sockptr.h:49) ? __pfx_mctp_dst_output (net/mctp/route.c:41) ? selinux_socket_sendmsg (security/selinux/hooks.c:5278) ____sys_sendmsg (net/socket.c:775 (discriminator 1) net/socket.c:790 (discriminator 1) net/socket.c:2684 (discriminator 1)) ? __pfx_____sys_sendmsg (net/socket.c:1131) ? __pfx_copy_msghdr_from_user (net/socket.c:2590) ? update_cfs_rq_load_avg (kernel/sched/fair.c:5478) ___sys_sendmsg (net/socket.c:2738) ? __pfx____sys_sendmsg (net/socket.c:2625) ? perf_event_task_tick (./include/linux/rcupdate.h:838) ? sched_tick (kernel/sched/core.c:5818) ? clockevents_program_event (kernel/time/clockevents.c:372) ? fdget (./include/linux/rcupdate.h:873 fs/file.c:1100) __sys_sendmsg (net/socket.c:2770) ? __pfx___sys_sendmsg (net/socket.c:2751) do_syscall_64 (arch/x86/entry/syscall_64.c:63) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) </TASK> Fix by publishing only once the object is fully initialised: __mctp_dev_get() runs under rcu_read_lock() only and hands this object to readers as soon as mctp_ptr is assigned, so they must never observe mdev->dev == NULL. | |
| Title | net/mctp: publish the mctp_dev only after it is initialised | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-10-18T15:48:58.470Z
Reserved: 2026-09-25T10:25:14.371Z
Link: CVE-2026-98812
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-10-18T16:17:35.313
Modified: 2026-10-18T16:17:35.313
Link: CVE-2026-98812
Redhat
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OpenCVE Enrichment
Updated: 2026-10-18T20:30:17Z