commit e0123be7a908d1a4b7c43d0817b9ecccf2bd1416
Author: Pablo Neira Ayuso <pablo@netfilter.org>
Date:   Thu Mar 27 16:32:16 2025 +0100

    parser_json: reject empty concatention in set key and data
    
    Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/src/parser_json.c b/src/parser_json.c
index 17bc38b565ae..513e0b10f028 100644
--- a/src/parser_json.c
+++ b/src/parser_json.c
@@ -1729,6 +1729,13 @@ static struct expr *json_parse_dtype_expr(struct json_ctx *ctx, json_t *root)
 			}
 			compound_expr_add(expr, i);
 		}
+
+		if (list_empty(&expr->expressions)) {
+			json_error(ctx, "Empty concatenation");
+			expr_free(expr);
+			return NULL;
+		}
+
 		return expr;
 	} else if (json_is_object(root)) {
 		const char *key;