CVE-2026-63266 Arbitrary file write via calcext:data-mappings, sql provider and Firebird backup functionality
An attacker can write arbitrary files to any user-writable location by crafting a LibreOffice Calc document with a malicious Firebird database link.
- 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-2026-63266?
CVE-2026-63266 is a medium-severity path traversal vulnerability in The Document Foundation LibreOffice, published on 5 Oct 2026. 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 Calc can link a cell range to an external data source, and the link is saved in the document. Through such a link a document could open an embedded Firebird database that wrote a file to any location the user could write to. In fixed versions an embedded Firebird database can open or create files only inside its own private directory.
Weakness: CWE-22
Which versions are affected by CVE-2026-63266?
How do I fix CVE-2026-63266?
Apply the vendor's patch.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-63266 being exploited?
There is no known exploitation of CVE-2026-63266 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-63266, ECHO-c6b4-711f-c38e, GHSA-5436-5r9x-m4jv, MINI-6xrr-hxr3-w4qj, UBUNTU-CVE-2026-63266.