Cisco : Security Vulnerabilities, CVEs, Published In December 2000 (Denial of service)

Buffer overflow in CiscoSecure ACS Server 2.4(2) and earlier allows remote attackers to cause a denial of service and possibly execute arbitrary commands via a large TACACS+ packet.

Buffer overflow in CSAdmin module in CiscoSecure ACS Server 2.4(2) and earlier allows remote attackers to cause a denial of service and possibly execute arbitrary commands via a large packet.

The HTTP server in Cisco IOS 12.0 through 12.1 allows local users to cause a denial of service (crash and reload) via a URL containing a "?/" string.