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.
Credits
Claude, found by Anthropic using agents to study the security of open-source projects