This indicates an attack attempt against an Information Disclosure vulnerability in Edge.
The vulnerability is due to improper validation of user supplied data when handling crafted HTTP Requests. A remote attacker can exploit this to gain unauthorized access to sensitive information on the affected machines via crafted packets.
Microsoft Edge on Windows 10 Version 1803 for 32-bit Systems
Microsoft Edge on Windows 10 Version 1803 for x64-based Systems
Information Disclosure: Remote attackers can gain sensitive information from vulnerable systems
Apply the most recent upgrade or patch from the vendor.