CVE-2023-52456

A flaw was found in the UART driver handling RS485 communication in the Linux Kernel when an unexpected closure of the TTY port occurs, such as during a userland application crash. In this scenario, the imx_uart_shutdown function disables the UART interface and the Transmission Complete (TC) interrupt. Subsequently, the imx_uart_stop_tx function attempts to stop the transmission but exits prematurely if the transmission is incomplete, expecting the now-disabled TC interrupt to complete the process. This results in the transmission state machine remaining in a deadlocked SEND state, leaving the TX_EN pin low and rendering the RS485 interface non-functional. This vulnerability can lead to communication failures and potential system instability.

This vulnerability is considered of Moderate severity because it leads to a deadlock in the transmission state machine, rendering the RS485 interface non-functional and potentially disrupting serial communication. While it does not directly compromise data integrity or security, it can cause significant operational issues, especially in systems relying on continuous and reliable RS485 communication. The impact is limited to the availability of the serial interface rather than the broader system, and it requires a specific condition—an unexpected TTY port closure during transmission—to be triggered.

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.

No mitigation is currently available for this vulnerability. Make sure to perform the updates as they become available.