Cisco Cisco IOS Software Release 12.4(2)XB6

Devices running Cisco IOS versions 12.0S, 12.2, 12.3 or 12.4 and configured for Multiprotocol 
Label Switching (MPLS) Virtual Private Networks (VPNs) or VPN Routing and Forwarding Lite 
(VRF Lite) and using Border Gateway Protocol (BGP) between Customer Edge (CE) and Provider 
Edge (PE) devices may permit information to propagate between VPNs.

Workarounds are available to help mitigate this vulnerability. 

This issue is triggered by a logic error when processing extended communities on the PE device. 

This issue cannot be deterministically exploited by an attacker. 

Cisco has released free software updates that address these vulnerabilities. Workarounds that 
mitigate these vulnerabilities are available.

This advisory is posted at 

CSCsd85587

A vulnerability has been discovered in a third party cryptographic library which is used by a number 
of Cisco products. This vulnerability may be triggered when a malformed Abstract Syntax Notation 
One (ASN.1) object is parsed. Due to the nature of the vulnerability it may be possible, in some 
cases, to trigger this vulnerability without a valid certificate or valid application-layer credentials 
(such as a valid username or password).

Successful repeated exploitation of any of these vulnerabilities may lead to a sustained 
Denial-of-Service (DoS); however, vulnerabilities are not known to compromise either the 
confidentiality or integrity of the data or the device. These vulnerabilities are not believed to allow 
an attacker will not be able to decrypt any previously encrypted information.

The vulnerable cryptographic library is used in the following Cisco products:

Cisco IOS, documented as Cisco bug ID CSCsd85587 

Cisco IOS XR, documented as Cisco bug ID CSCsg41084 

Cisco PIX and ASA Security Appliances, documented as Cisco bug ID CSCse91999 

Cisco Unified CallManager, documented as Cisco bug ID CSCsg44348 

Cisco Firewall Service Module (FWSM)

This vulnerability is also being tracked by CERT/CC as VU#754281.

Cisco has made free software available to address this vulnerability for affected customers. There 
are no workarounds available to mitigate the effects of the vulnerability.

http://www.cisco.com/warp/public/707/cisco-sa-20070522-crypto.shtml

.

Another related advisory is posted together with this Advisory. It also describes vulnerabilities 
related to cryptography that affect Cisco IOS. A combined software table for Cisco IOS only is 
available at 

can be used to choose a software release which fixes all security vulnerabilities published as of 
May 22, 2007. The related advisory is published at 

There are no open caveats in this release.