This indicates an attack attempt to exploit an Integer Overflow vulnerability in Apache Subversion.
The vulnerability is due to an error while the vulnerable application handles maliciously crafted requests. A remote attacker may be able to exploit this to launch an arbitrary code execution or cause denial of service conditions on the affected machine.
Apache Software Foundation Subversion 1.7.0 to 1.8.14
Apache Software Foundation Subversion 1.9.0 to 1.9.2
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the latest update from the vendor.