syslog-ng Open Source Edition versions below 2.0.6 and Premium Edition versions below 2.1.8 suffer from a denial of service vulnerability.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/61881/ZSA-2007-029.txt
Source: https://packetstormsecurity.com/files/61881/ZSA-2007-029.txt.html