An inconsistency between the serial core functions uart_write_room() and uart_write() in the Linux kernel creates an infinite loop when a PORT_UNKNOWN serial port has an uninitialized transmit buffer. Drivers that rely on tty_write_room() to decide whether space is available for writing will repeatedly call write, receive zero bytes, and remain in the loop, causing the system to hang. This constitutes a denial‑of‑service condition triggered by misinitialized serial ports.

Any Linux kernel build that contains the buggy serial core code before the fix is affected. The vendors listed are Linux:Linux, which covers all standard Linux kernels. Specific affected kernel versions are not enumerated in the advisory, so any kernel prior to the commit that introduced the patch is potentially vulnerable.

The advisory does not provide CVSS or EPSS scores, and the vulnerability is not in the CISA Known Exploited Vulnerabilities catalog. Based on the description, the bug could be exploited by an entity with the ability to load or configure a driver that opens a PORT_UNKNOWN serial port, leading to a system hang. The lack of explicit exploitation details limits the assessment, but the potential for widespread denial of service remains for affected systems.