This indicates an attack attempt against a buffer-overflow vulnerability in HP OpenView NNM.
The vulnerability is caused by an error when the vulnerable software handles
a request with a malicious "OvJavaLocale" header. It allows a remote attacker to execute arbitrary code via sending a crafted HTTP query.
HP OpenView NNM v.7.53
System Compromise: Remote attackers can gain control of vulnerable systems.
Upgrade to the latest version, available from the vendor's website.
See HP's security bulletin HPSBMA02563 SSRT100165 for details.