CVE-2010-0587 in Unified Communications Manager
Summary
by MITRE
Cisco Unified Communications Manager (aka CUCM, formerly CallManager) 4.x before 4.3(2)SR2, 6.x before 6.1(5), 7.x before 7.1(3a)su1, and 8.x before 8.0(1) allows remote attackers to cause a denial of service (process failure) via a malformed SCCP StationCapabilitiesRes message with an invalid MaxCap field, aka Bug ID CSCtc38985.
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Analysis
by VulDB Data Team • 05/01/2026
Cisco Unified Communications Manager represents a critical component in enterprise voice communication infrastructure serving as the central call processing server for IP telephony systems. The vulnerability described in CVE-2010-0587 specifically targets the Skinny Client Control Protocol implementation within CUCM versions across multiple release branches including 4.x, 6.x, 7.x, and 8.x. This flaw manifests when the system receives a malformed SCCP StationCapabilitiesRes message containing an invalid MaxCap field value that exceeds the expected parameter boundaries. The vulnerability operates at the protocol level where the system fails to properly validate incoming SCCP messages before processing them, creating an exploitable condition that can be leveraged by remote attackers without authentication requirements. This represents a classic buffer overflow scenario where the system attempts to process malformed data without adequate input sanitization, leading to process termination and subsequent denial of service conditions that can disrupt enterprise communication networks.
The technical execution of this vulnerability involves crafting a specially formatted SCCP StationCapabilitiesRes message that contains an invalid MaxCap field value. According to CWE-129, this represents an input validation flaw where insufficient checks are performed on the maximum capacity parameter that should be constrained to predefined acceptable ranges. The attacker can send this malformed message from any remote location to the CUCM server, exploiting the lack of proper bounds checking within the SCCP message parsing routine. The system's failure to validate the MaxCap field value results in a process crash or unexpected termination, effectively causing a denial of service condition that renders the affected communication services unavailable. This vulnerability directly maps to ATT&CK technique T1499.004 which describes network denial of service attacks targeting network infrastructure components.
The operational impact of this vulnerability extends beyond simple service disruption as it affects enterprise communication infrastructure that may support critical business operations including emergency services, customer support, and internal communications. When exploited successfully, the vulnerability can cause complete unavailability of the affected CUCM server, requiring manual intervention for system recovery and potentially impacting business continuity. The exploit requires minimal privileges and can be executed remotely, making it particularly dangerous for organizations with limited security monitoring capabilities. Organizations relying on CUCM for voice services may experience significant operational disruption, especially in mission-critical environments where communication availability is paramount. The vulnerability affects multiple major release versions, indicating a widespread exposure across different generations of the Cisco Unified Communications Manager platform.
Mitigation strategies for this vulnerability include immediate application of Cisco's security patches and updates as released in the affected software versions. Organizations should upgrade to the patched versions specified in the CVE description including 4.3(2)SR2, 6.1(5), 7.1(3a)su1, and 8.0(1) respectively. Network segmentation and access control measures should be implemented to limit exposure of CUCM servers to untrusted networks while maintaining necessary communication pathways. The implementation of network intrusion detection systems can help identify and alert on malformed SCCP traffic patterns that may indicate exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify similar input validation issues within the communication infrastructure. Additionally, implementing proper monitoring and alerting mechanisms for process failures and service disruptions can help detect exploitation attempts and reduce response time. The vulnerability highlights the importance of robust input validation and proper error handling in telephony protocols, aligning with industry best practices for secure network protocol implementation and the principles outlined in the OWASP Top Ten security framework.