Cisco Cisco IOS Software Release 12.4(4)T

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 

CSCsi93683

Symptoms: In Cisco IOS software that is running the Bidirectional Forwarding Detection (BFD) 
protocol, attempts to remove BFD sessions may fail. 

Conditions: The symptom has been observed after the maximum number of supported sessions has 
been configured. The maximum number is 128 in most but not all releases. 

Workaround: There is no workaround. 

CSCsd81350

Symptoms: When asynchronous serial interfaces are used as member links in multilink PPP bundles, 
the router may crash due to memory corruption.

Conditions: This problem can occur under conditions where multilink fragmentation is done, and 
where the bundle includes at least one member link that is an asynchronous interface.

Workaround: Disable fragmentation on the bundle interface for any bundle that may include 
asynchronous links as members. Alternatively, if the use of multilink is not a requirement, disable 
multilink on the asynchronous interfaces. 

CSCsh82513

Symptoms: The output of the show isdn active command may show disconnected calls.

Conditions: This symptom is observed on a Cisco router when analog modem calls are made after a 
normal ISDN digital call has been made.

Workaround: There is no workaround. 

Cisco IOS Release 12.4(9)T3 is a rebuild release for Cisco IOS Release 12.4(9)T. The caveats in this 
section are resolved in Cisco IOS Release 12.4(9)T3 but may be open in previous Cisco IOS releases. 

The following information is provided for each caveat: