Medium [CVE-2026-74459] es58x_read_bulk_callback: fix RX buffer leak on URB resubmit failure

In the Linux kernel, the following vulnerability has been resolved: can: etas_es58x: es58x_read_bulk_callback(): fix RX buffer leak on URB resubmit failure es58x_read_bulk_callback() resubmits the RX URB after processing a received packet. If the resubmit succeeds, the URB remains anchored and will be handled by the normal RX path or by teardown.

However, if usb_submit_urb() fails, the callback unanchors the URB and then returns directly. This skips the existing free_urb path, so the coherent transfer buffer allocated with usb_alloc_coherent() is not released.

Reuse the existing free_urb path after a resubmit failure so that the RX coherent buffer is freed before leaving the callback. A memory leak occurs in the `es58x_read_bulk_callback()` function when an Urban Request Block (URB) resubmission fails.

This failure prevents the proper release of the associated receive (RX) buffer, leading to a gradual exhaustion of system memory. This can ultimately result in a denial of service (DoS) for affected systems.

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-772.

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.