There is no input validation on the Locale property in an apt transaction. An unprivileged user can supply a full path to a writable directory, which lets aptd read a file as root. Having a symlink in place results in an error message if the file exists, and no error otherwise. This way an unprivileged user can check for the existence of any files on the system as root.
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
| Link | Tags |
|---|---|
| https://www.eyecontrol.nl/blog/the-story-of-3-cves-in-ubuntu-desktop.html | third party advisory exploit |
| https://ubuntu.com/security/notices/USN-4537-1 | third party advisory patch |