Medium [CVE-2026-80645] prevent a bad dereference in tsi721_db_dpc

In the Linux kernel, the following vulnerability has been resolved: rapidio/tsi721: prevent a bad dereference in tsi721_db_dpc() With a list_for_each() loop, if we don't find the item we are looking for in the list, then the loop exits with the iterator, which is "dbell" in this loop, pointing to invalid memory.

This code uses the "found" variable to determine if we have found the doorbell we are looking for or not. However, the problem that the "found" variable needs to be set to false at the start of each iteration, otherwise after the first correct doorbell, then everything is marked as found.

Reset the "found" to false at the start of the iteration and move the variable inside the loop. This vulnerability arises from incorrect handling of a variable within a specific loop in the `tsi721_db_dpc()` function.

If a particular item is not found, the system attempts to access invalid memory. This could allow a local attacker to trigger a system crash, leading to a Denial of Service (DoS).

Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-824.

Red Hat lists Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9 as not affected.