CVE-2017-6656: A vulnerability in Session Initiation Protocol (SIP) call handling of Cisco IP Phone 8800 Series devices co...

Security readout for executives and security teams

CVE-2017-6656 is a denial-of-service issue in Cisco IP Phone 8800 Series SIP call handling. A remote unauthenticated attacker could cause the SIP process to restart, dropping all active calls on the affected phone. The evidence points to voice availability disruption, not data theft or device takeover. Exposure is most likely in environments still operating Cisco IP Phone 8800 Series devices on affected SIP firmware. Business risk is higher where phones are reachable from untrusted networks or support critical operations such as contact centers, emergency coordination, or executive communications. Prioritize remediation for phone fleets supporting revenue, safety, customer support, or incident response. This vulnerability is unlikely to expose sensitive data based on the supplied evidence, but it can interrupt communications and degrade business continuity. Mitigation focus: Inventory Cisco IP Phone 8800 Series devices and firmware versions.; Upgrade affected devices to a Cisco fixed release or current vendor-recommended firmware.; Restrict SIP access to trusted call-control infrastructure where operationally possible..

Prepared

Jun 13, 2026, 04:43 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.