CVE-2025-38265

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

serial: jsm: fix NPE during jsm_uart_port_init

No device was set which caused serial_base_ctrl_add to crash.

BUG: kernel NULL pointer dereference, address: 0000000000000050 Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 16 UID: 0 PID: 368 Comm: (udev-worker) Not tainted 6.12.25-amd64 #1 Debian 6.12.25-1 RIP: 0010:serial_base_ctrl_add+0x96/0x120 Call Trace: <TASK> serial_core_register_port+0x1a0/0x580 ? __setup_irq+0x39c/0x660 ? __kmalloc_cache_noprof+0x111/0x310 jsm_uart_port_init+0xe8/0x180 [jsm] jsm_probe_one+0x1f4/0x410 [jsm] local_pci_probe+0x42/0x90 pci_device_probe+0x22f/0x270 really_probe+0xdb/0x340 ? pm_runtime_barrier+0x54/0x90 ? __pfx___driver_attach+0x10/0x10 __driver_probe_device+0x78/0x110 driver_probe_device+0x1f/0xa0 __driver_attach+0xba/0x1c0 bus_for_each_dev+0x8c/0xe0 bus_add_driver+0x112/0x1f0 driver_register+0x72/0xd0 jsm_init_module+0x36/0xff0 [jsm] ? __pfx_jsm_init_module+0x10/0x10 [jsm] do_one_initcall+0x58/0x310 do_init_module+0x60/0x230

Tested with Digi Neo PCIe 8 port card.

A null pointer dereference was discovered in the jsm_uart_port_init() function of the jsm serial driver due to a missing initialization of the uart_port.dev field. This issue triggers a kernel crash when the driver attempts to register the serial port via serial_base_ctrl_add(). Exploitation requires the ability to load and initialize a kernel module (e.g., via modprobe or insmod), which is restricted to privileged users. As such, only a local user with administrative rights (CAP_SYS_MODULE or equivalent) can trigger the vulnerable code path, justifying PR:H.

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.