CVE-2023-53219: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-53219 is a vulnerability discovered in the Linux kernel affecting the Universal DVB card driver (netup_unidvb). The issue was disclosed on September 15, 2025, and primarily affects the media subsystem of the Linux kernel (NVD).

The vulnerability is a use-after-free bug that occurs in the netup_unidvb driver when handling timer operations. Specifically, when the Universal DVB card is detaching, netup_unidvb_dma_fini() uses del_timer() to stop the dma->timeout timer. However, if the timer handler netup_unidvb_dma_timeout() is running, del_timer() cannot stop it, potentially leading to a use-after-free condition (NVD).

The vulnerability affects various Linux distributions and their kernel packages. Ubuntu has rated this vulnerability as 'Medium' priority and has implemented fixes across multiple supported versions including Ubuntu 22.04 LTS (jammy), 20.04 LTS (focal), and 18.04 LTS (bionic) (Ubuntu).

The issue has been fixed by changing del_timer() to del_timer_sync(). Multiple Linux distributions have released patches, including Ubuntu which has implemented fixes in various kernel versions: 5.15.0-83.92 for Ubuntu 22.04 LTS, 5.4.0-162.179 for Ubuntu 20.04 LTS, and 5.4.0-162.179~18.04.1 for Ubuntu 18.04 LTS (Ubuntu).