Merge pull request #5854 from Chaosmeister/backwardsmotionnullguard

Guard against null in vehicle_update_track_motion_backwards_get_new_track()

distribution/changelog.txt

@@ -22,6 +22,7 @@
 - Fix: [#1705] Time Twister's Medieval entrance has incorrect scrolling (original bug)
 - Fix: [#3178, #5456] Paths with non-ASCII characters not handled properly on macOS.
 - Fix: [#3479] Building in pause mode creates too many floating numbers, crashing the game
+- Fix: [#3565] Multiplayer server crash
 - Fix: [#3681] Steel Twister rollercoaster always shows all track designs
 - Fix: [#3846, #5749] Crash when testing coaster with a diagonal lift in block brake mode
 - Fix: [#4054] Sorting rides by track type: Misleading research messages

src/openrct2/ride/vehicle.c

@@ -7706,6 +7706,9 @@ static bool vehicle_update_track_motion_backwards_get_new_track(rct_vehicle *veh
         0
         );
 
+    if (mapElement == NULL)
+        return false;
+
     bool nextTileBackwards = true;
     sint32 direction;
 //loc_6DBB08:;