A vulnerability in the DHCP version 6 (DHCPv6) server implementation of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.
The vulnerability is due to improper parsing of malformed DHCPv6 packets. An attacker could exploit this vulnerability by sending malformed DHCPv6 packets to be processed by an affected device. An exploit could allow the attacker to cause a memory leak and eventual reload of an affected device.
Cisco has confirmed the vulnerability in a security advisory and released software updates.
Indicators of Compromise
Customers are advised to use the Cisco Software Checker tool to determine whether devices are running an affected release of Cisco IOS Software. The tool also provides information about releases that correct the vulnerabilities.
Cisco has published a list of affected Cisco IOS XE Software releases in the security advisory. The "Vendor Announcements" section of this alert contains a link to the advisory.
The vulnerability is due to improper parsing of malformed DHCPv6 packets by a device running an affected release of Cisco IOS Software.
An attacker could exploit this vulnerability by sending malformed DHCPv6 packets to a targeted device. Processing the malformed DHCPv6 packets could allow the attacker to cause a memory leak and eventually reload the device, resulting in a DoS condition.
To exploit this vulnerability, an attacker may need access to trusted, internal network resources behind a firewall to send malformed DHCPv6 packets to a targeted device. This access requirement reduces the possibility of a successful exploit.
Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.
Administrators are advised to apply the appropriate updates.
Cisco customers with active contracts can obtain updates through the Software Center at the following link: Cisco. Cisco customers without contracts can obtain upgrades by contacting the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via email at firstname.lastname@example.org.
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Cisco Multivendor Vulnerability Alerts respond to vulnerabilities identified in third-party vendors' products. These alerts contain information compiled from diverse sources and provide comprehensive technical descriptions, objective analytical assessments, workarounds and practical safeguards, and links to vendor advisories and patches.