Live › vulnerability › CVE-2026-98812
Go to dashboardIn the Linux kernel's MCTP networking code, a new MCTP device can be made visible to readers before its net_device pointer is set, so a concurrent sender dereferences NULL and crashes the kernel. The sources do not state a confirmed code-execution or privilege-escalation path.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 21:57 UTC. All times on this page are UTC.
Only systems running a Linux kernel with MCTP support where MCTP devices are added, which is a niche protocol. Systems that do not load the MCTP module are unlikely to be exposed; the sources do not say more.
No product ranges from the sources yet.
uname -r and compare against the fixed kernel versions listed in the NVD entry (unknown in the sources).lsmod | grep mctp or ls /proc/net/mctp (unknown in the sources whether this is the exact check).Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
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.
This page as .md · .json · in your agent: get_signal("CVE-2026-98812")
NVD data is provided by NIST and is public domain. Posts quoted belong to their authors.