This indicates an attack attempt against a Code Execution vulnerability in PHP.
The vulnerability is due to an error when the vulnerable software handles a maliciously crafted serialized object. A remote attacker may be able to exploit this to execute arbitrary code on the affected systems.
PHP Group PHP 7.0.x up to 7.0.14
PHP Group PHP 7.1.0
System Compromise: Remote attacker can gain control of vulnerable systems.
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