A vulnerability in the IPv6 to IPv4 subsystem of Cisco IOS Software could allow an unauthenticated, remote attacker to cause a standby Performance Routing Engine (PRE) to leak a small portion of memory on a targeted system, resulting in a denial of service (DoS) condition. The vulnerability is due to a failure to free a portion of memory allocated to store the IPv6 address of a connecting customer premises equipment (CPE) device when a specific error condition is encountered. An attacker who can trigger a specific type of failed CPE negotiation could cause the standby PRE to leak a small portion of memory, resulting in a DoS condition. Cisco has confirmed the vulnerability and released software updates. Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.
The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
| Version | Description | Section | Status | Date |
| 1.0 | Initial Release | NA | Final | 2015-Jun-22 |
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