There's a longer land path that starts in or near Senegal and ends in China. But they miss it because it goes near the Dead Sea, and they treat anything below sea level as water.
It seems like that path crosses the Suez canal. I think it's fair that bridges and/or tunnels don't count.
If you are talking about the trail from Cape Town to Vladivostok, that one is not a straight line.
That would an interesting finding!
Indeed, this route would be about 13,250 km, or about 2,000 km longer than the one TLA suggests.
http://www.gcmap.com/mapui?P=10%B0+24%27+41.4%22+N,+14%B0+31...
Or, using nearby airports: https://www.greatcirclemap.com/?routes=gucy-vmmc