CVE-2026-63821

In the Linux kernel, the following vulnerability has been resolved:

wifi: rtw88: usb: fix memory leaks on USB write failures

When rtwusbwrite_port() fails to submit a USB Request Block (URB) (e.g., due to device disconnect or ENOMEM), the completion callback is never executed.

Currently, the driver ignores the return value of rtwusbwriteport() in rtwusbwritedata() and rtwusbtxaggskb(). Because these functions rely on the completion callback to free the socket buffers (skbs) and the transaction control block (txcb), a submission failure results in: 1. A memory leak of the allocated skb in rtwusbwritedata(). 2. A memory leak of the txcb structure and all aggregated skbs in rtwusbtxagg_skb().

Fix this by checking the return value of rtwusbwriteport(). If it fails, explicitly free the skb in rtwusbwritedata(), and properly purge the txackqueue and free the txcb in rtwusbtxaggskb().

The issue was discovered in practice during device disconnect/reconnect scenarios and memory pressure conditions. Tested by verifying normal TX operation continues after the fix without regressions.