CVE-2026-63275 Stack buffer overflow in CFF font hint handling
A stack buffer overflow in LibreOffice's CFF font hint handling allows attackers to execute arbitrary code or cause a crash via malicious documents.
- 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-2026-63275?
CVE-2026-63275 is a medium-severity memory corruption vulnerability in The Document Foundation LibreOffice, published on 22 Sep 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 can read CFF fonts, which may be embedded in documents. A stack buffer overflow existed when reading the hints of a glyph. The number of hints was checked against the wrong bound, so a glyph declaring more hints than the array can hold wrote past its end. In fixed versions the hint count is checked against the capacity the array really has.
Weakness: CWE-787
Which versions are affected by CVE-2026-63275?
How do I fix CVE-2026-63275?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-63275 being exploited?
There is no known exploitation of CVE-2026-63275 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-63275, ECHO-0c4c-8c22-be6a, GHSA-fh9h-5g6m-wc43, MINI-r5f9-v9fw-f59q, UBUNTU-CVE-2026-63275.