A file upload vulnerability in exists in Trend Micro Apex One server build 11110. Using a malformed Content-Length header in an HTTP PUT message sent to URL /officescan/console/html/cgi/fcgiOfcDDA.exe, an unauthenticated remote attacker can upload arbitrary files to the SampleSubmission directory (i.e., PCCSRVTEMPSampleSubmission) on the server. The attacker can upload a large number of large files to fill up the file system on which the Apex One server is installed.