Cisco issued three \u201ccritical\u201d security warnings for its DNA Center users \u2013 two having a Common Vulnerability Scoring System rating of 9.8 out of 10.\nThe two worst problems involve Cisco Data Center Network Manager (DCNM).\u00a0 Cisco DNA Center controls access through policies using Software-Defined Access, automatically provision through Cisco DNA Automation, virtualize devices through Cisco Network Functions Virtualization (NFV), and lower security risks through segmentation and Encrypted Traffic Analysis.\n\nIn one advisory Cisco said a vulnerability in the web-based management interface of DCNM could let an attacker obtain a valid session cookie without knowing the administrative user password by sending a specially crafted HTTP request to a specific web servlet that is available on affected devices. The vulnerability is due to improper session management on affected DCNM software.\nThe vulnerability affects DCNM software releases prior to Release 11.1(1). Cisco said it removed the affected web servlet completely in DCNM Software Release\u00a011.1(1).\nAnother critical warning was issued for DCNM on a vulnerability that lets an attacker create arbitrary files on the underlying DCNM filesystem by sending specially crafted data to a specific web servlet that is available on affected devices. \u00a0\nCisco said the vulnerability is due to incorrect permission settings in affected DCNM software. A successful exploit could allow the attacker to write arbitrary files on the filesystem and execute code with root privileges on the affected device.\nIn DCNM Software Release 11.0(1) and earlier, an attacker would need to be authenticated to the DCNM web-based management interface to exploit this vulnerability, Cisco said.\nThe third vulnerability \u2013 with a CVSS score of 9.3 \u2013 defines a vulnerability in DNA Center that could let an unauthenticated, adjacent attacker bypass authentication and access critical internal services. An attacker could exploit this vulnerability by connecting an unauthorized network device to the subnet designated for cluster services. A successful exploit could allow an attacker to reach internal services that are not hardened for external access, Cisco said.\nThe vulnerability is due to insufficient access restriction to ports necessary for system operation, the company stated.\u00a0\nIn this case Cisco said a workaround is available for customers who cannot upgrade to a fixed release. To coordinate implementation of the workaround, contact the Cisco Technical Assistance Center (TAC).\nCisco said it has released free software updates that address the vulnerabilities described in these advisories. \u00a0\nThe critical warnings this week follow another critical DNA Center notice last week. Then Cisco detailed a critical warning \u2013 with a CVSS rating of 9.3\u00a0\u2013 about vulnerability in its DNA Center software that could let an unauthenticated attacker exploit this weakness by connecting an unauthorized network device to the subnet designated for cluster services.\nA successful exploit could let an attacker reach internal services that are not hardened for external access, Cisco stated.\u00a0 The vulnerability is due to insufficient access restriction to ports necessary for system operation, and Cisco discovered the issue during internal security testing, the company stated.\nThis vulnerability affects Cisco\u00a0DNA Center Software releases prior to 1.3, and it is fixed in version 1.3 and releases after that. \u00a0\u00a0\nCisco wrote that system updates are available for installation from the Cisco cloud and are not available for download from the Software Center on Cisco.com. To upgrade to a fixed release of Cisco\u00a0DNA Center Software, administrators can use the System Updates feature of the software.