CVE-2022-50767: 
Linux Kernel vulnerability analysis and mitigation

CVE-2022-50767 is a use-after-free (UAF) vulnerability in the Linux kernel's fbdev smscufx USB framebuffer driver. It occurs when a USB device is physically removed, triggering multiple UAF conditions in the device handling process. The vulnerability affects Linux kernel versions from the initial commit up through 4.9.331, 4.14.297, 4.19.263, 5.4.222, 5.10.152, 5.15.76, 6.0.6, and pre-6.1 releases. It was published on December 24, 2025, with patches backported across multiple stable kernel branches. No CVSS base score has been formally assigned; Feedly estimates the severity as Medium (Red Hat CVE, ENISA EUVD).

The root cause is improper resource management (CWE-416: Use After Free) in the smscufx framebuffer driver (drivers/video/fbdev/smscufx.c). When a USB device is physically disconnected, the driver's teardown path fails to properly sequence memory deallocation, allowing freed memory regions to be accessed subsequently. The fix introduces a ufx_ops_destroy() function assigned to the .fb_destroy callback of fb_ops; this function calls kref_put(), which ultimately invokes ufx_free() to safely release resources and prevent multiple UAF conditions. Exploitation requires local physical access to insert and remove a USB device connected to the affected driver (Red Hat CVE, Red Hat Bugzilla).

Successful exploitation of this vulnerability could result in kernel crashes (denial of service) or, in more severe scenarios, arbitrary code execution in kernel context due to the use-after-free memory corruption. The vulnerability is confined to systems with the smscufx USB framebuffer driver loaded and requires physical access to trigger device removal. There is no evidence of data exfiltration risk or lateral movement potential beyond the local system (Red Hat CVE, Feedly).

Update to a patched Linux kernel version: 4.9.332, 4.14.298, 4.19.264, 5.4.223, 5.10.153, 5.15.77, 6.0.7, or 6.1 and later. As a temporary workaround, restrict physical USB device removal on sensitive systems or blacklist the smscufx kernel module (modprobe -r smscufx / add blacklist smscufx to /etc/modprobe.d/) if the driver is not required. SUSE has also issued kernel security updates addressing this CVE (Red Hat CVE, Red Hat Bugzilla).