diff --git a/res/ari/resource_channels.c b/res/ari/resource_channels.c
index 4d5228168a..aaf04a3f88 100644
--- a/res/ari/resource_channels.c
+++ b/res/ari/resource_channels.c
@@ -152,6 +152,13 @@ void ast_ari_mute_channel(struct ast_variable *headers, struct ast_mute_channel_
 		return;
 	}
 
+	if (ast_strlen_zero(args->direction)) {
+		ast_ari_response_error(
+			response, 400, "Bad Request",
+			"Direction is required");
+		return;
+	}
+
 	if (!strcmp(args->direction, "in")) {
 		direction = AST_MUTE_DIRECTION_READ;
 	} else if (!strcmp(args->direction, "out")) {
@@ -181,6 +188,13 @@ void ast_ari_unmute_channel(struct ast_variable *headers, struct ast_unmute_chan
 		return;
 	}
 
+	if (ast_strlen_zero(args->direction)) {
+		ast_ari_response_error(
+			response, 400, "Bad Request",
+			"Direction is required");
+		return;
+	}
+
 	if (!strcmp(args->direction, "in")) {
 		direction = AST_MUTE_DIRECTION_READ;
 	} else if (!strcmp(args->direction, "out")) {