VulnerabilityPublished 18 Oct 2026Updated 21 Oct 2026

CVE-2026-98812: Linux kernel · net/mctp: publish the mctp_dev only after it is initialised

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in f37f42e6e039a48c2dcf6c079b9f7fbc864ab7ef : update Linux kernel when convenient.

Data as of 26 Oct 2026, 14:18 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in f37f42e6e039a48c2dcf6c079b9f7fbc864ab7ef, af6e4f931afc2d670d133aa2bedc8b6e3753c618, aadf655e8ea9a8ffa24bb8d69f504572e8d18181 +2

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 583be982d93479ea3d85091b0fd0b01201ede87d, < f37f42e6e039a48c2dcf6c079b9f7fbc864ab7ef	Fixed in f37f42e6e039a48c2dcf6c079b9f7fbc864ab7ef
LinuxLinux	Affected ≥ 583be982d93479ea3d85091b0fd0b01201ede87d, < af6e4f931afc2d670d133aa2bedc8b6e3753c618	Fixed in af6e4f931afc2d670d133aa2bedc8b6e3753c618
LinuxLinux	Affected ≥ 583be982d93479ea3d85091b0fd0b01201ede87d, < aadf655e8ea9a8ffa24bb8d69f504572e8d18181	Fixed in aadf655e8ea9a8ffa24bb8d69f504572e8d18181
LinuxLinux	Affected ≥ 583be982d93479ea3d85091b0fd0b01201ede87d, < 63120572edde85bb2b70b0ed4d4817ed52247613	Fixed in 63120572edde85bb2b70b0ed4d4817ed52247613
LinuxLinux	Affected ≥ 583be982d93479ea3d85091b0fd0b01201ede87d, < 288ef37e0c463192dbb6436e61cdc07ce666dcb9	Fixed in 288ef37e0c463192dbb6436e61cdc07ce666dcb9
LinuxLinux	Affected =5.15	Fixed in–

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.

References

Community reviews

Loading reviews…