A vulnerability in the implementation of the virtual fragmentation reassembly (VFR) feature for IP version 6 (IPv6) in Cisco IOS Software could allow an
unauthenticated, remote attacker to cause an affected device to hang or reload, resulting in a denial of service (DoS) condition.

vulnerability is due to a race condition while accessing the reassembly
queue for IPv6 fragments.

An attacker could exploit this vulnerability
by sending a crafted stream of valid IPv6 fragments. Repeated
exploitation may result in a sustained DoS condition.
Cisco has released free software updates that address this vulnerability.

There are no workarounds for this vulnerability.

This advisory is available at the following link:http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20130925-ipv6vfr
Note: The September 25, 2013, Cisco IOS Software Security Advisory bundled publication includes eight Cisco Security Advisories.

All advisories address vulnerabilities in Cisco IOS Software. Each Cisco IOS Software Security Advisory lists the Cisco IOS Software releases that correct the vulnerability or vulnerabilities detailed in the advisory as well as the Cisco IOS Software releases that correct all Cisco IOS Software vulnerabilities in the September 2013 bundled publication.
Individual publication links are in “Cisco Event Response: Semiannual Cisco IOS Software Security Advisory Bundled Publication” at the following link:

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