CVE-2026-31518

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

esp: fix skb leak with espintcp and async crypto

When the TX queue for espintcp is full, esp_output_tail_tcp will
return an error and not free the skb, because with synchronous crypto,
the common xfrm output code will drop the packet for us.

With async crypto (esp_output_done), we need to drop the skb when
esp_output_tail_tcp returns an error.