diff --git a/src/normal.c b/src/normal.c
index a06d61e..16b4b45 100644
--- a/src/normal.c
+++ b/src/normal.c
@@ -2562,7 +2562,14 @@
 	if (nchar == K_DEL || nchar == K_KDEL)
 	    n /= 10;
 	else if (VIM_ISDIGIT(nchar))
+	{
+	    if (n > LONG_MAX / 10)
+	    {
+		clearopbeep(cap->oap);
+		break;
+	    }
 	    n = n * 10 + (nchar - '0');
+	}
 	else if (nchar == CAR)
 	{
 #ifdef FEAT_GUI