BinTec X4000 Access router, and possibly other versions, allows remote attackers to cause a denial of service via a SYN port scan, which causes the router to hang.
https://exchange.xforce.ibmcloud.com/vulnerabilities/6323
http://marc.info/?l=bugtraq&m=98697054804197&w=2
http://marc.info/?l=bugtraq&m=98659862317070&w=2
http://marc.info/?l=bugtraq&m=98644414226344&w=2
http://archives.neohapsis.com/archives/bugtraq/2001-04/0145.html