CVE-2003-0677: Cisco CSS 11000 routers on the CS800 chassis allow remote attackers to cause a denial of service (CPU consu...

Security readout for executives and security teams

CVE-2003-0677 is a denial-of-service issue in Cisco CSS 11000 devices on the CS800 chassis. A high volume of TCP SYN traffic to a circuit IP address could consume CPU or reboot the device, interrupting services that depend on that platform. Exposure is likely limited to organizations still operating legacy Cisco CSS 11000 CS800 chassis systems, especially where circuit IP addresses are reachable from untrusted or poorly filtered networks. Treat this as a legacy infrastructure availability risk. It is not known to be actively exploited from the supplied evidence, but exposed unsupported devices could still create outage risk for dependent services. Mitigation focus: Identify any Cisco CSS 11000 devices on CS800 chassis still in production.; Check Cisco support or archived vendor guidance for applicable fixes or workarounds.; Restrict untrusted access to circuit IP addresses wherever operationally possible..

Prepared

Jun 30, 2026, 09:00 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.