CVE-2025-39810

In the Linux kernel, the following vulnerability has been resolved:

bnxt_en: Fix memory corruption when FW resources change during ifdown

bnxt_set_dflt_rings() assumes that it is always called before any TC has been created. So it doesn't take bp->num_tc into account and assumes that it is always 0 or 1.

In the FW resource or capability change scenario, the FW will return flags in bnxt_hwrm_if_change() that will cause the driver to reinitialize and call bnxt_cancel_reservations(). This will lead to bnxt_init_dflt_ring_mode() calling bnxt_set_dflt_rings() and bp->num_tc may be greater than 1. This will cause bp->tx_ring[] to be sized too small and cause memory corruption in bnxt_alloc_cp_rings().

Fix it by properly scaling the TX rings by bp->num_tc in the code paths mentioned above. Add 2 helper functions to determine bp->tx_nr_rings and bp->tx_nr_rings_per_tc.

This vulnerability is rated Moderate for Red Hat Enterprise Linux 8 and 9. A memory corruption flaw exists in the bnxt_en kernel driver, which could be triggered when firmware resources change during an interface down operation. Triggering this vulnerability requires elevated privileges (ex. CAP_NET_ADMIN) as configuring traffic classes is a privileged operation. If the vulnerability is triggered, then the primary impact will be on integrity and availability, as the bug can cause kernel memory corruption in the kernel heap structures related to network i/o, which in turn can lead to a kernel crash. Confidentiality is most probably not impacted, as an out-of-bounds write could overwrite adjacent kernel memory, but no direct read exposure is implied.

Red Hat Enterprise Linux 6, 7, and Red Hat In-Vehicle OS are not affected as the vulnerable code is not present in these versions.

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.