CVE-2026-63821wifi: rtw88: usb: fix memory leaks on USB write failures

Official description

In the Linux kernel, the following vulnerability has been resolved: wifi: rtw88: usb: fix memory leaks on USB write failures When rtw_usb_write_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 rtw_usb_write_port() in rtw_usb_write_data() and rtw_usb_tx_agg_skb(). 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 rtw_usb_write_data(). 2. A memory leak of the txcb structure and all aggregated skbs in rtw_usb_tx_agg_skb(). Fix this by checking the return value of rtw_usb_write_port(). If it fails, explicitly free the skb in rtw_usb_write_data(), and properly purge the tx_ack_queue and free the txcb in rtw_usb_tx_agg_skb(). 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.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/2b2060c2075a72bc2de43ce5e1b9347d6c5e27bb
• https://git.kernel.org/stable/c/53fed4061a09755de99c89fdc7fae5b794da455f
• https://git.kernel.org/stable/c/200d58c851b8f63f77a05570072dd20f79bc3681
• https://git.kernel.org/stable/c/8206d173d18ef5a077423119f4e9a93cb3a6f4eb
• https://git.kernel.org/stable/c/6b964941bbfe6e0f18b1a5e008486dbb62df440a