--- screen-write.c.orig	2023-12-12 21:17:02.960288969 +0100
+++ screen-write.c	2023-12-12 21:18:07.498869550 +0100
@@ -2120,6 +2120,10 @@
 			return (0);
 	}
 
+    /* Check if this combined character would be too long. */
+    if (last.data.size + ud->size > sizeof last.data.data)
+        return (0);
+
 	/* Combining; flush any pending output. */
 	screen_write_collect_flush(ctx, 0, __func__);