diff --git a/ccan/README b/ccan/README
index d1fe493f5..978ba64a4 100644
--- a/ccan/README
+++ b/ccan/README
@@ -1,3 +1,3 @@
 CCAN imported from http://ccodearchive.net.
 
-CCAN version: init-2491-ga1f9c169
+CCAN version: init-2494-g4f20b75c
diff --git a/ccan/ccan/opt/opt.c b/ccan/ccan/opt/opt.c
index d4601dfbb..d376a598d 100644
--- a/ccan/ccan/opt/opt.c
+++ b/ccan/ccan/opt/opt.c
@@ -189,7 +189,8 @@ bool opt_unregister(const char *names)
 	if (found == -1)
 		return false;
 	opt_count--;
-	memmove(&opt_table[found], &opt_table[found+1], opt_count - found);
+	memmove(&opt_table[found], &opt_table[found+1],
+		(opt_count - found) * sizeof(opt_table[found]));
 	return true;
 }