CVE-2019-9852 Insufficient URL encoding flaw in allowed script location check
Attackers can bypass script location restrictions via URL encoding to execute arbitrary pre-installed macros, requiring an upgrade to LibreOffice.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2019-9852?
CVE-2019-9852 is a high-severity path traversal vulnerability in Canonical Ubuntu Linux, published on 15 Aug 2019. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
LibreOffice has a feature where documents can specify that pre-installed macros can be executed on various script events such as mouse-over, document-open etc. Access is intended to be restricted to scripts under the share/Scripts/python, user/Scripts/python sub-directories of the LibreOffice install. Protection was added, to address CVE-2018-16858, to avoid a directory traversal attack where scripts in arbitrary locations on the file system could be executed. However this new protection could be bypassed by a URL encoding attack. In the fixed versions, the parsed url describing the script location is correctly encoded before further processing. This issue affects: Document Foundation LibreOffice versions prior to 6.2.6.
Which versions are affected by CVE-2019-9852?
It affects 5 products.
Products include Canonical Ubuntu Linux, Debian Debian Linux, Fedoraproject Fedora, Libreoffice Libreoffice, Opensuse Leap.
How do I fix CVE-2019-9852?
Upgrade to a fixed version.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2019-9852 being exploited?
There is no known exploitation of CVE-2019-9852 in the wild and no public exploit code.
Other vulnerabilities in Canonical Ubuntu Linux
Sources
Also known as DEBIAN-CVE-2019-9852, GHSA-vgrf-j225-8963, UBUNTU-CVE-2019-9852.