A vulnerability in the Representational State Transfer (REST) interface of the Cisco Unified Communications Manager IM and Presence Service could allow an unauthenticated, remote attacker to cause a partial denial of service (DoS) condition because the Cisco Session Initiation Protocol (SIP) proxy service can unexpectedly restart.
The vulnerability is due to lack of proper input validation of the HTTP request when it is sent to the REST interface. An attacker could exploit this vulnerability by sending a crafted HTTP request to the REST interface of the affected application. An exploit could allow the attacker to cause a partial DoS condition because the Cisco SIP proxy service can unexpectedly restart.
Cisco has confirmed the vulnerability; however, software updates are not available.
To exploit the vulnerability, an unauthenticated attacker must reach the REST interface and send a crafted HTTP request to the device. This requirement may reduce the likelihood 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.