This indicates an attack attempt to exploit a Directory Traversal Vulnerability in Xen Project XAPI.
The vulnerability is due to an error in the vulnerable application when handling a maliciously crafted request. An attacker can exploit this to disclose contents of arbitrary files on the affected machine via a crafted request.
Xen Project XAPI v1.13.0 and later
Information Disclosure: Remote attackers can gain sensitive information from vulnerable systems.
Apply the most recent upgrade or patch from the vendor: