diff --git a/src/editfns.c b/src/editfns.c
index f275f33fc52..f7c26b900a0 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -4919,7 +4919,7 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
 		  else if (discarded[bytepos] == 1)
 		    {
 		      position++;
-		      if (translated == info[fieldn].start)
+		      if (fieldn < nspec && translated == info[fieldn].start)
 			{
 			  translated += info[fieldn].end - info[fieldn].start;
 			  fieldn++;
@@ -4939,7 +4939,7 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
 		  else if (discarded[bytepos] == 1)
 		    {
 		      position++;
-		      if (translated == info[fieldn].start)
+		      if (fieldn < nspec && translated == info[fieldn].start)
 			{
 			  translated += info[fieldn].end - info[fieldn].start;
 			  fieldn++;