CVE-2026-81572: Local Privilege Escalation in CodeMeter Runtime on Windows
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.
Affected Software
Event History
Frequently Asked Questions
Does exploitation require remote access or user interaction?
No. The vulnerability is locally exploitable and does not require user interaction, but the attacker needs local low-privileged access.
What attacker-controlled condition is needed for exploitation?
The attacker must be able to create an NTFS reparse point, such as a junction or symbolic link, at the predictable temporary-file location under C:\CM-Stick and redirect it to an arbitrary system path.
Which operation should defenders focus on when assessing exposure?
The affected behavior is associated with cmu.exe when it is run with the --create-io --file C: arguments. That operation creates a predictable temporary file without properly checking the directory and file paths for NTFS reparse points.