The libertas Wi‑Fi driver in the Linux kernel contains a flaw in the usb_tx_block routine: it submits a USB request block (URB) without first confirming that a previous transmission on that URB has completed. When a second call occurs while the URB remains active, usb_submit_urb triggers the warning 'URB submitted while active.' This warning reflects a lack of proper serialization of USB traffic and can lead to driver instability or a denial of service if the situation repeats during rapid firmware loads or sustained USB activity. No crash or data corruption is explicitly documented; the impact is limited to potential disruption of the wireless adapter’s operation.

Any Linux kernel that ships the unpatched libertas Wi‑Fi driver is affected. The advisory does not specify exact kernel revisions, so all distributions or custom kernels containing the libertas module without the commit that adds usb_kill_urb before each usb_submit_urb may be vulnerable. The only vendor listed is Linux.

The CVSS score of 5.5 coupled with an EPSS score below 1 % indicates moderate severity but a low probability of exploitation. The vulnerability is not listed in the CISA KEV catalog, and no public exploits are known. Attackers would need local or device‑level access to trigger the condition, for example by rapidly reloading firmware or forcing many USB transfers, which could cause driver instability. In practice, the risk remains confined to repeated warning logs and the potential for intermittent wireless connectivity loss.