Cisco has announced three security bulletins regarding issues in the Cisco IOS software. Cisco IOS is the software used on the vast majority of Cisco routers and all Cisco network switches.
Crafted TCP Packet Can Cause Denial of Service – The Cisco IOS Transmission Control Protocol (TCP) listener in certain versions of Cisco IOS software is vulnerable to a remotely-exploitable memory leak that may lead to a denial of service condition. This vulnerability only applies to traffic destined to the Cisco IOS device.
IPv6 Routing Header Vulnerability – Processing a specially crafted IPv6 Type 0 Routing header can crash a device running Cisco IOS software. This vulnerability does not affect IPv6 Type 2 Routing header which is used in mobile IPv6. IPv6 is not enabled by default in Cisco IOS.
Crafted IP Option Vulnerability – Cisco routers and switches running Cisco IOS® or Cisco IOS XR software may be vulnerable to a remotely exploitable crafted IP option Denial of Service (DoS) attack. Exploitation of the vulnerability may potentially allow for arbitrary code execution.
The vulnerability may be exploited after processing an Internet Control Message Protocol (ICMP) packet, Protocol Independent Multicast version 2 (PIMv2) packet, Pragmatic General Multicast (PGM) packet, or URL Rendezvous Directory (URD) packet containing a specific crafted IP option in the packet´s IP header. No other IP protocols are affected by this issue.