FreeBSD Security Advisory – The sendfile system call suffers from a write-only file permission bypass vulnerability.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/63655/FreeBSD-SA-08-03.sendfile.txt
Source: https://packetstormsecurity.com/files/63655/FreeBSD-SA-08-03.sendfile.txt.html