CVE-2023-54093: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-54093 is a null pointer dereference vulnerability in the Linux kernel's media: anysee DVB-USB driver, specifically within the anysee_master_xfer function. A local, low-privileged attacker can craft malicious I2C messages with a null buf pointer and zero len field to bypass existing input checks and trigger a kernel crash. The vulnerability affects Linux kernel versions from the initial commit up to the patched releases (4.14.326, 4.19.295, 5.4.257, 5.10.197, 5.15.133, 6.1.55, 6.5.5, and 6.6). It was published on December 24, 2025, with a CVSS v3.1 base score of 5.5 (Medium) (Red Hat CVE, Feedly).

The root cause is a null pointer dereference (CWE-476) in the anysee_master_xfer function of the drivers/media/usb/dvb-usb/anysee.c driver. When user-controlled I2C message data (msg) is processed, the function checks msg[i].buf for null but fails to validate msg[i].len; when both buf is null and len is zero, the null check is bypassed and the code proceeds to access msg[i].buf[0] without a sanity check, causing a null pointer dereference. The fix adds an explicit check on msg[i].len before accessing the buffer, mirroring a similar fix applied to the az6027 driver (commit 0ed554fd769a). Exploitation requires local access and the ability to interact with the anysee DVB-USB device interface (Red Hat CVE, Red Hat Bugzilla).

Successful exploitation results in a kernel null pointer dereference, causing a system crash (denial of service). The impact is limited to availability — there is no confidentiality or integrity impact — but a crash can disrupt all services running on the affected host. The vulnerability requires local low-privileged access, limiting its scope to systems where an attacker already has a foothold and the anysee driver is loaded (Red Hat CVE, Feedly).

Update the Linux kernel to a patched version: 4.14.326, 4.19.295, 5.4.257, 5.10.197, 5.15.133, 6.1.55, 6.5.5, or 6.6 and later. If an immediate kernel update is not feasible, consider blacklisting or unloading the anysee DVB-USB kernel module (modprobe -r anysee) on systems where the hardware is not in use, to eliminate the attack surface. Apply least-privilege access controls to limit which users can interact with USB media devices (Red Hat CVE, Red Hat Bugzilla).