diff --git a/conf.h b/conf.h
index eee209ff..7f81ae10 100644
--- a/conf.h
+++ b/conf.h
@@ -314,7 +314,7 @@ void _cf_warn_node_value(struct __sourceloc __whence, const struct cf_om_node *n
 void _cf_warn_no_array(struct __sourceloc __whence, const struct cf_om_node *node, int reason);
 void _cf_warn_unsupported_node(struct __sourceloc __whence, const struct cf_om_node *node);
 void _cf_warn_unsupported_children(struct __sourceloc __whence, const struct cf_om_node *parent);
-void _cf_warn_list_overflow(struct __sourceloc __whence, const struct cf_om_node *node);
+void _cf_warn_list_overflow(struct __sourceloc __whence, const struct cf_om_node *node, const char *fmt, ...);
 void _cf_warn_incompatible(struct __sourceloc __whence, const struct cf_om_node *node, const struct cf_om_node *orig);
 void _cf_warn_incompatible_children(struct __sourceloc __whence, const struct cf_om_node *parent);
 void _cf_warn_array_key(struct __sourceloc __whence, const struct cf_om_node *node, int reason);
@@ -330,7 +330,7 @@ void _cf_warn_array_value(struct __sourceloc __whence, const struct cf_om_node *
 #define cf_warn_no_array(node, reason)	     _cf_warn_no_array(__WHENCE__, node, reason)
 #define cf_warn_unsupported_node(node)	     _cf_warn_unsupported_node(__WHENCE__, node)
 #define cf_warn_unsupported_children(parent) _cf_warn_unsupported_children(__WHENCE__, parent)
-#define cf_warn_list_overflow(node)	     _cf_warn_list_overflow(__WHENCE__, node)
+#define cf_warn_list_overflow(node, fmt, ...) _cf_warn_list_overflow(__WHENCE__, node, fmt, ##__VA_ARGS__)
 #define cf_warn_incompatible(node, orig)     _cf_warn_incompatible(__WHENCE__, node, orig)
 #define cf_warn_incompatible_children(parent) _cf_warn_incompatible_children(__WHENCE__, parent)
 #define cf_warn_array_key(node, reason)	     _cf_warn_array_key(__WHENCE__, node, reason)
diff --git a/conf_om.c b/conf_om.c
index b8e6d8ef..de3c49b6 100644
--- a/conf_om.c
+++ b/conf_om.c
@@ -493,7 +493,10 @@ void _cf_warn_childrenv(struct __sourceloc __whence, const struct cf_om_node *pa
 {
   unsigned i;
   for (i = 0; i < parent->nodc; ++i) {
-    _cf_warn_nodev(__whence, parent->nodv[i], NULL, fmt, ap);
+    va_list ap1;
+    va_copy(ap1, ap);
+    _cf_warn_nodev(__whence, parent->nodv[i], NULL, fmt, ap1);
+    va_end(ap1);
     _cf_warn_childrenv(__whence, parent->nodv[i], fmt, ap);
   }
 }
@@ -673,8 +676,13 @@ void _cf_warn_array_value(struct __sourceloc __whence, const struct cf_om_node *
     _cf_warn_node(__whence, node, NULL, "array element -- %s", strbuf_str(b));
 }
 
-void _cf_warn_list_overflow(struct __sourceloc __whence, const struct cf_om_node *node)
+void _cf_warn_list_overflow(struct __sourceloc __whence, const struct cf_om_node *node, const char *fmt, ...)
 {
-  _cf_warn_node(__whence, node, NULL, "list overflow");
-  _cf_warn_children(__whence, node, "list overflow");
+  va_list ap;
+  va_start(ap, fmt);
+  _cf_warn_nodev(__whence, node, NULL, fmt, ap);
+  va_end(ap);
+  va_start(ap, fmt);
+  _cf_warn_childrenv(__whence, node, fmt, ap);
+  va_end(ap);
 }
diff --git a/conf_parse.c b/conf_parse.c
index 4bbfd904..b6899868 100644
--- a/conf_parse.c
+++ b/conf_parse.c
@@ -302,7 +302,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 	assert(n == NELS(array->av)); \
 	result |= CFARRAYOVERFLOW; \
 	for (; i < node->nodc; ++i) \
-	  cf_warn_list_overflow(node->nodv[i]); \
+	  cf_warn_list_overflow(node->nodv[i], "list overflow, only %zu elements allowed", NELS(array->av)); \
       } \
       array->ac = n; \
       qsort(array->av, array->ac, sizeof array->av[0], (int (*)(const void *, const void *)) keycmp); \
diff --git a/tests/config b/tests/config
index 2b657383..acb5b1bb 100755
--- a/tests/config
+++ b/tests/config
@@ -279,6 +279,26 @@ test_InterfaceDropDgramIncompatible() {
       --error-pattern='config file.*loaded despite defects.*incompatible'
 }
 
+doc_TooManyValues="Too many config values"
+setup_TooManyArgs() {
+   setup_servald
+   for i in {0..9}; do
+      executeOk_servald config set "interfaces.$i.match" "eth$i"
+   done
+}
+test_TooManyArgs() {
+   execute --stderr --executable=$servald config \
+      set "interfaces.99.match" "eth11" \
+      set "interfaces.99.exclude" "on" \
+      set "interfaces.99.port" "1234" \
+      set "interfaces.99.broadcast.send" "on" \
+      set "interfaces.99.broadcast.route" "on" \
+      set "interfaces.99.unicast.send" "on" \
+      set "interfaces.99.unicast.route" "on"
+   tfw_cat --stdout --stderr
+   assertExitStatus '==' 2
+}
+
 #TODO move to another test script?
 doc_CmdUsage="Show help usage"
 test_CmdUsage() {