This indicates an attack attempt to exploit a Security Bypass vulnerability in Oracle Java SE.
Incorrect certificate signature checks in Java SE allows an attacker to impersonate as the real server in a SSL protected communication. An attacker could impersonate as a legitimate server with a specially crafted certificate. This can result in a MITM attack.
Oracle Java SE 17.0.2 and 18
Oracle GraalVM Enterprise Edition 21.3.1 and 188.8.131.52
Security Bypass: Remote attackers can bypass security checks of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.