Cisco has released an update that addresses a vulnerability in a series of switches and routers.
The flaw is in the Firewall Services Module (FWSM) for its Catalyst 6500 series switches and 7600 series routers.
An attacker could have caused a denial of service (DoS) attack if they sent "specially crafted ICMP" messages to the Firewall Services Module, Cisco said.
Cisco said it had not yet seen any cases of the flaw being exploited, but had observed data streams that had triggered it by accident.
The US-CERT (United States Computer Emergency Readiness Team) encouraged users and administrators to review the advisory and apply the necessary updates and workarounds.
This new flaw follows a separate patch the networking company released on Wednesday for its IOS XR software, used on some of its routers.
This could have led to routing inconsistencies and denial-of-service.
