{"id":"CVE-2026-98812","summary":"net/mctp: publish the mctp_dev only after it is initialised","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mctp: publish the mctp_dev only after it is initialised\n\nmctp_add_dev() links the new mctp_dev into dev-\u003emctp_ptr before mdev-\u003edev\nis assigned, so a reader that picks the device up in that window\ndereferences a net_device pointer that is still NULL:\n\nKASAN: null-ptr-deref in range [0x00000000000000b0-0x00000000000000b7]\nCall Trace:\n \u003cTASK\u003e\n ? __pfx_mctp_sendmsg (./include/linux/sockptr.h:49)\n ? __pfx_mctp_dst_output (net/mctp/route.c:41)\n ? selinux_socket_sendmsg (security/selinux/hooks.c:5278)\n ____sys_sendmsg (net/socket.c:775 (discriminator 1) net/socket.c:790\n (discriminator 1) net/socket.c:2684 (discriminator 1))\n ? __pfx_____sys_sendmsg (net/socket.c:1131)\n ? __pfx_copy_msghdr_from_user (net/socket.c:2590)\n ? update_cfs_rq_load_avg (kernel/sched/fair.c:5478)\n ___sys_sendmsg (net/socket.c:2738)\n ? __pfx____sys_sendmsg (net/socket.c:2625)\n ? perf_event_task_tick (./include/linux/rcupdate.h:838)\n ? sched_tick (kernel/sched/core.c:5818)\n ? clockevents_program_event (kernel/time/clockevents.c:372)\n ? fdget (./include/linux/rcupdate.h:873 fs/file.c:1100)\n __sys_sendmsg (net/socket.c:2770)\n ? __pfx___sys_sendmsg (net/socket.c:2751)\n do_syscall_64 (arch/x86/entry/syscall_64.c:63)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n \u003c/TASK\u003e\n\nFix by publishing only once the object is fully initialised:\n__mctp_dev_get() runs under rcu_read_lock() only and hands\nthis object to readers as soon as mctp_ptr is assigned, so\nthey must never observe mdev-\u003edev == NULL.","modified":"2026-10-19T02:47:35.496756769Z","published":"2026-10-18T15:48:58.470Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98812.json","cna_assigner":"Linux"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/63120572edde85bb2b70b0ed4d4817ed52247613"},{"type":"WEB","url":"https://git.kernel.org/stable/c/aadf655e8ea9a8ffa24bb8d69f504572e8d18181"},{"type":"WEB","url":"https://git.kernel.org/stable/c/af6e4f931afc2d670d133aa2bedc8b6e3753c618"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f37f42e6e039a48c2dcf6c079b9f7fbc864ab7ef"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98812.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98812"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"583be982d93479ea3d85091b0fd0b01201ede87d"},{"fixed":"af6e4f931afc2d670d133aa2bedc8b6e3753c618"},{"fixed":"63120572edde85bb2b70b0ed4d4817ed52247613"},{"fixed":"f37f42e6e039a48c2dcf6c079b9f7fbc864ab7ef"},{"fixed":"aadf655e8ea9a8ffa24bb8d69f504572e8d18181"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98812.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.15.0"},{"fixed":"6.12.113"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.56"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.10"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98812.json"}}],"schema_version":"1.9.0"}