CVE-2025-68265

A flaw was found in the Linux kernel’s NVMe host driver (drivers/nvme/host/core.c) related to the lifetime management of the controller’s admin request queue. Under certain conditions, namespaces could retain stale references to the controller’s admin request queue after the controller was torn down. Accessing these stale references could lead to a use-after-free condition in the kernel, potentially resulting in memory corruption or system instability.

A use-after-free flaw was found in the Linux kernel NVMe host driver related to the lifetime management of a controller's admin request queue. After a controller was torn down, namespaces could retain stale references to the controller's admin request queue, and subsequent use of those stale references (for example, when a local user with privileges issues NVMe ioctl commands) could trigger a use-after-free in the kernel, potentially resulting in memory corruption, a kernel panic, or system instability. Red Hat Product Security rates this flaw as having a MODERATE security impact: exploitation requires local access and privileges, and the primary consequence is denial of service. Red Hat Enterprise Linux 6 is not affected because the vulnerable code is not present in that stream. For the affected Red Hat Enterprise Linux and Red Hat In-Vehicle OS streams, the fix has been deferred; the residual risk is that a privileged local user could trigger a use-after-free and crash the system, causing denial of service. The CVE.org record assigns this flaw a higher severity (CVSS 3.1 score 7.8, IMPORTANT) with high confidentiality and integrity impact, whereas Red Hat's CVSS 3.1 score of 5.5 reflects an availability-only impact (C:N/I:N/A:H).

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, the nvme kernel module can be blacklisted to prevent it from being loaded. This will prevent the system from utilizing NVMe devices.

To blacklist the nvme module:

1. Create a file named blacklist-nvme.conf in /etc/modprobe.d/ with the following content:

   blacklist nvme
   

2. Regenerate the initramfs to ensure the blacklist is applied during boot:
   • For RHEL 7, 8, 9, 10: dracut -f -v
3. Reboot the system for the changes to take effect.

Warning: Blacklisting the nvme module will disable all NVMe storage devices on the system, which may impact system functionality if NVMe devices are used for boot, root filesystem, or other critical operations.