Cisco BroadWorks SIP Denial of Service Vulnerability (CVE-2025-20165)
CVE number is CVE-2025-20165 a CVSS score of 7.5 has been assigned.
This vulnerability affects Cisco BroadWorks, regardless of device configuration.
A vulnerability in the SIP processing subsystem of Cisco BroadWorks could allow an unauthenticated, remote attacker to halt the processing of incoming SIP requests, resulting in a denial of service (DoS) condition.
This vulnerability is due to improper memory handling for certain SIP requests. An attacker could exploit this vulnerability by sending a high number of SIP requests to an affected system. A successful exploit could allow the attacker to exhaust the memory that was allocated to the Cisco BroadWorks Network Servers that handle SIP traffic. If no memory is available, the Network Servers can no longer process incoming requests, resulting in a DoS condition that requires manual intervention to recover.
To successfully exploit this vulnerability, an attacker would need to completely saturate the memory assigned to the Cisco BroadWorks Network Servers. Because administrators can allocate an arbitrary amount of memory to these servers, the time and the amount of SIP requests that are necessary to cause a DoS condition varies.
Administrators can monitor the current status of the used memory and, if the usage becomes close to the maximum, restart the BroadWorks services on the Network Servers to avoid the DoS condition. During a restart, existing calls are not interrupted, but some services may be temporarily unavailable. For information on how to monitor memory utilization of Cisco BroadWorks Network Servers, see Section 19, Cisco BroadWorks System Monitoring, of the Cisco BroadWorks Maintenance Guide.
This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bw-sip-dos-mSySbrmt
I am one of the editors here at www.systemtek.co.uk I am a UK based technology professional, with an interest in computer security and telecoms.