CVE-2026-98723: nvmet: copy the hostid into the ctrl before creating PR pc_refs
In the Linux kernel, the following vulnerability has been resolved:
nvmet: copy the hostid into the ctrl before creating PR pcrefs
Commit 6202783184bf ("nvmet: Improve nvmetallocctrl() interface and implementation") added a second uuidcopy() of args->hostid near the end of nvmetallocctrl(), and commit 7b658153f1b8 ("nvmet: Remove duplicate uuidcopy") removed the original copy that sat before nvmetctrlinitpr() instead of the new one.
Since then nvmetctrlinitpr() snapshots ctrl->hostid into the per-controller per-namespace reservation refs while the uuidcopy() from the connect data runs later, after the controller is published. The ctrl is allocated with kzalloc(), so every pcref created on this path stores the nil UUID.
pcref->hostid has a single consumer: nvmetprsetctrltoabort() matches it against the preempted registrant's hostid to kill and drain the victim's in-flight I/O for Preempt and Abort. The match can never hit with the nil UUID, so whenever a namespace with reservations enabled exists before a host connects, which includes every reconnect, Preempt and Abort silently degrades into a plain Preempt: the preempting host sees success while the victim's in-flight I/O is still in the air.
Copy the hostid where the rest of the connect data is consumed, before the controller is published and before nvmetctrlinitpr() takes its snapshot.
Affected Software
Event History
Frequently Asked Questions
Which deployments are affected by this behavior?
It affects NVMe target deployments where a namespace has reservations enabled before a host connects. The description states this includes every reconnect.
What must occur for the vulnerability to have an impact?
A host must perform a Preempt and Abort against a preempted registrant. Because the reservation reference stores a nil host UUID, the target cannot match the victim controller and therefore does not kill and drain that controller's in-flight I/O.
How does the failure present operationally?
The preempting host sees the Preempt and Abort operation succeed, but it silently behaves like a plain Preempt. The victim's in-flight I/O is not aborted and drained as intended.