FreyrSCADA/IEC-60870-5-104 server v21.06.008 allows remote attackers to cause a denial of service by sending specific message sequences.
https://github.com/FreyrSCADA/IEC-60870-5-104/issues/6
https://drive.google.com/drive/folders/1pBPZR59d_rlixH7ZysUmmbOEZvjZV9g1