net/mctp: publish the mctp_dev only after it is initialised

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-98812
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-18 16:17:35 UTC
Updated2026-10-19 10:19:45 UTC
DescriptionIn 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.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 583be982d93479ea3d85091b0fd0b01201ede87d af6e4f931afc2d670d133aa2bedc8b6e3753c618 git Not specified
CNA Linux Linux affected 583be982d93479ea3d85091b0fd0b01201ede87d 63120572edde85bb2b70b0ed4d4817ed52247613 git Not specified
CNA Linux Linux affected 583be982d93479ea3d85091b0fd0b01201ede87d f37f42e6e039a48c2dcf6c079b9f7fbc864ab7ef git Not specified
CNA Linux Linux affected 583be982d93479ea3d85091b0fd0b01201ede87d aadf655e8ea9a8ffa24bb8d69f504572e8d18181 git Not specified
CNA Linux Linux affected 5.15 Not specified
CNA Linux Linux unaffected 5.15 semver Not specified
CNA Linux Linux unaffected 6.12.113 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.56 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.10 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/f37f42e6e039a48c2dcf6c079b9f7fbc864ab7ef 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/63120572edde85bb2b70b0ed4d4817ed52247613 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/aadf655e8ea9a8ffa24bb8d69f504572e8d18181 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/af6e4f931afc2d670d133aa2bedc8b6e3753c618 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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