diff --git a/src/rec-fex.c b/src/rec-fex.c
index 96648ec..db1ae24 100644
--- a/src/rec-fex.c
+++ b/src/rec-fex.c
@@ -722,7 +722,7 @@ rec_fex_append (rec_fex_t fex,
 
   if (fex->num_elems >= REC_FEX_MAX_ELEMS)
     {
-      fprintf (stderr,
+      fprintf (stderr, "%s",
                _("internal error: REC_FEX_MAX_ELEMS exceeded.  \
 Please report this.\n"));
       return NULL;
diff --git a/src/rec-types.c b/src/rec-types.c
index 4d4fda2..a98a21f 100644
--- a/src/rec-types.c
+++ b/src/rec-types.c
@@ -894,7 +894,7 @@ rec_type_new (const char *str)
       break;
     case REC_TYPE_NONE:
       /* This point should not be reached.  */
-      fprintf (stderr,
+      fprintf (stderr, "%s",
                _("internal error: rec-types: got REC_TYPE_NONE from \
 rec_type_parse_type_kind() in rec_type_new().\n"));
       exit (EXIT_FAILURE);
diff --git a/src/rec-utils.c b/src/rec-utils.c
index 4c60e6c..d70af09 100644
--- a/src/rec-utils.c
+++ b/src/rec-utils.c
@@ -82,7 +82,7 @@ rec_extract_file (const char *str)
 
   if (regcomp (&regexp, "[ \n\t]" REC_FILE_REGEXP, REG_EXTENDED) != 0)
     {
-      fprintf (stderr,
+      fprintf (stderr, "%s",
                _("internal error: rec_int_rec_extract_file:\
  error compiling regexp.\n"));
       return NULL;
@@ -112,7 +112,7 @@ rec_extract_url (const char *str)
 
   if (regcomp (&regexp, REC_URL_REGEXP, REG_EXTENDED) != 0)
     {
-      fprintf (stderr,
+      fprintf (stderr, "%s",
                _("internal error:\
  rec_int_rec_extract_url: error compiling regexp.\n"));
       return NULL;
@@ -143,7 +143,7 @@ rec_extract_type (const char *str)
   /* TODO: use a REC_TYPE_NAME_RE  */
   if (regcomp (&regexp, REC_FNAME_RE, REG_EXTENDED) != 0)
     {
-      fprintf (stderr,
+      fprintf (stderr, "%s",
                _("internal error:\
  rec_int_rec_extract_url: error compiling regexp.\n"));
       return NULL;
@@ -287,7 +287,7 @@ rec_match_int (const char *str,
 
   if (regcomp (&regexp, reg, flags) != 0)
     {
-      fprintf (stderr, _("internal error: rec_match: error compiling regexp.\n"));
+      fprintf (stderr, "%s", _("internal error: rec_match: error compiling regexp.\n"));
       return false;
     }