The Linux kernel’s MMC driver vub300 contains a NULL‑pointer dereference when the controller disconnects. If a controller is not deregistered before the driver data reference count is decremented, a NULL dereference or use‑after‑free can occur. This flaw can crash the kernel or provide denial of service; it may be exploitable by an attacker who can trigger a disconnect event, which is inferred from the need to cause a controller disconnect. The weakness is a NULL pointer dereference, classified as CWE‑476.

Affected systems are all Linux kernel versions that contain the vulnerable vub300 MMC driver before the patch was applied. The vulnerability is not tied to a specific kernel release but applies to any kernel in which the driver has not been updated to perform controller deregistration before releasing the reference on disconnect.

The CVSS score of 5.5 indicates moderate severity, while the EPSS score of less than 1% reflects a very low probability of exploitation in the wild. The vulnerability is not listed in the CISA KEV catalog. Attackers would likely need local access to the system to trigger an MMC disconnect and exploit the flaw; this inference comes from the requirement to cause a controller disconnect. A successful exploit could cause a kernel panic.