CVE-2026-63273 Heap buffer overflow in PDF import encryption handling
A heap buffer overflow in LibreOffice Draw allows attackers to execute arbitrary code or cause a crash by providing a maliciously crafted encrypted PDF document.
- 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-2026-63273?
CVE-2026-63273 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 Draw can import PDF documents. A heap buffer overflow existed when importing an encrypted document. The length of the decryption key was taken from the document's own encryption dictionary and was used to fill a fixed size key buffer without being checked against it, so a length larger than that buffer wrote past its end. In fixed versions a declared key length larger than the buffer is rejected.
Weakness: CWE-787
Which versions are affected by CVE-2026-63273?
How do I fix CVE-2026-63273?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-63273 being exploited?
There is no known exploitation of CVE-2026-63273 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-63273, ECHO-ef2e-7ba4-f184, GHSA-254q-47m3-r67w, MINI-p52p-v3q2-3vwj, UBUNTU-CVE-2026-63273.