Local Privilege Escalation in CodeMeter Runtime on Windows

In CodeMeter Runtime from version 8.40 to (excluding) 8.41a and 9.00 to (excluding) 9.10, cmu.exe --create-io --file C: creates a predictable temporary file under C:\CM-Stick. The directory and file paths are not properly checked for NTFS reparse points, such as junctions or symbolic links, before file operations are performed. A local attacker can create a junction at the temporary file that points to an arbitrary system path. Because CodeMeter Runtime runs with System privileges, this could allow arbitrary files to be deleted with System privileges and potentially enable local privilege escalation.