Cisco Cisco IOS Software Release 12.4(23)

Workaround: There is no workaround.

CSCsi60004

Multiple voice-related vulnerabilities are identified in Cisco IOS software, one of which is also 
shared with Cisco Unified Communications Manager. These vulnerabilities pertain to the following 
protocols or features:

Session Initiation Protocol (SIP) 

Media Gateway Control Protocol (MGCP) 

Signaling protocols H.323, H.254 

Real-time Transport Protocol (RTP) 

Facsimile reception 

Cisco has made free software available to address these vulnerabilities for affected customers. Fixed 
Cisco IOS software listed in the Software Versions and Fixes section contains fixes for all 
vulnerabilities mentioned in this advisory.

There are no workarounds available to mitigate the effects of any of the vulnerabilities apart from 
disabling the protocol or feature itself. 

This advisory is posted at: 

CSCsi85641

Symptoms: When the Reverse Route Remote Peer option is enabled, packets may not be forwarded 
correctly.

Conditions: This symptom is observed when both CEF and the reverse-route remote-peer 
command are enabled. When you enable the debug ip cef drops command, typically, the following 
is shown:

CEF-Drop: Stalled adjacency for remote-physical-ip-addr on Ethernet1/0 

for destination remote-protected-ip-addr

CEF-Drop: Packet for remote-protected-ip-addr -- encapsulation

Workaround: Disable CEF.

Alternate Workaround: Add a next hop to the reverse route, for example, by entering the 
reverse-route remote-peer ip-address command. 

CSCsj10593

Symptoms: A terminating gateway (TGW) that is configured for Cisco ISDN Interconnect for Voice 
Gateways Solution may crash.

Conditions: This symptom is observed on a Cisco router that runs Cisco IOS interim 
Release 12.4(15.6) and that functions as a TGW with all PRI switch types from the user to the 
network side. The symptom occurs when the isdn test call interf ace interface-number 
dialing-string command is entered at the platform on which the call is initiated, when the originating 
gateway (OGW) is configured for the National ISDN (primary-ni) switch type, and when the TGW 
is configured for the NT DMS-100 (primary-dms100) switch type. The symptom may also affect 
Release 12.4T.

Workaround: There is no workaround.