This indicates an attack attempt to exploit an Information Disclosure vulnerability in Synology Photo Station.
The vulnerability is due to an error when the vulnerable software attempts to handle maliciously crafted packet. A remote attacker can exploit this to gain unauthorized access to sensitive information, leading to further attacks.
Synology Photo Station before 6.7.3-3432 and 6.3-2967
Information Disclosure: Remote attackers can gain sensitive information from vulnerable systems.
Refer to the vendor's advisory for updates: