This indicates an attack attempt to exploit an Access Control Bypass Vulnerability in the Apache mod_jk Connector.
The vulnerability is due to an error in the vulnerable application when handling a maliciously crafted request. A remote attacker may be able to exploit this to bypass security mechanisms within the context of the application, via a crafted request.
Apache mod_jk Connector 1.2.0 to 1.2.44
Security Bypass: Remote attackers can bypass security features of vulnerable systems.
Apply the most recent upgrade or patch from the vendor: