CVE-2010-0586 in IOS
Summary
by MITRE
Cisco IOS 12.1 through 12.4, when Cisco Unified Communications Manager Express (CME) or Cisco Unified Survivable Remote Site Telephony (SRST) is enabled, allows remote attackers to cause a denial of service (device reload) via a malformed Skinny Client Control Protocol (SCCP) message, aka Bug ID CSCsz49741, the "SCCP Request Handling Denial of Service Vulnerability."
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Analysis
by VulDB Data Team • 05/03/2026
The vulnerability described in CVE-2010-0586 represents a critical denial of service weakness affecting Cisco IOS versions 12.1 through 12.4 when specific unified communications features are enabled. This flaw specifically targets the Skinny Client Control Protocol implementation within Cisco's voice infrastructure, creating a scenario where remote attackers can manipulate the system into an unstable state that results in complete device reloads. The vulnerability manifests when Cisco Unified Communications Manager Express or Cisco Unified Survivable Remote Site Telephony functionality is active, making it particularly concerning for enterprise networks that rely on these communication protocols for business continuity.
The technical mechanism behind this vulnerability involves improper handling of malformed Skinny Client Control Protocol messages that are transmitted to affected Cisco IOS devices. The SCCP protocol serves as the communication interface between Cisco IP phones and the call manager, facilitating essential functions such as call setup, call control, and phone configuration. When the Cisco IOS software receives a specially crafted malformed SCCP message, the processing routine fails to properly validate or sanitize the incoming data, leading to a buffer overflow or stack corruption condition. This improper input handling represents a classic software flaw that falls under the CWE-121 category of buffer overflow conditions, where insufficient bounds checking allows malicious data to overwrite adjacent memory locations.
The operational impact of this vulnerability extends beyond simple service disruption, as it can cause complete network outages for voice communications across affected sites. Organizations utilizing Cisco Unified Communications Manager Express or SRST features would experience immediate and severe consequences including loss of voice connectivity, disruption of critical business operations, and potential security implications that could be exploited for further attacks. The remote nature of the attack means that threat actors do not require physical access or network credentials to exploit this vulnerability, making it particularly dangerous for environments where network security is not properly segmented. This vulnerability aligns with ATT&CK technique T1499.004 for network denial of service attacks and represents a significant threat to the availability component of the CIA triad.
Mitigation strategies for this vulnerability should focus on immediate patch application through Cisco's official security advisories, which would contain the necessary software updates to address the SCCP message handling flaw. Network administrators should also implement network segmentation and access controls to limit exposure of affected devices to untrusted networks. Additionally, monitoring systems should be configured to detect unusual SCCP traffic patterns that might indicate exploitation attempts, while implementing rate limiting or message filtering mechanisms to prevent malformed packets from reaching vulnerable systems. The vulnerability demonstrates the importance of proper input validation and robust error handling in network infrastructure software, emphasizing that even seemingly benign protocol implementations can become critical attack vectors when proper security measures are not in place. Organizations should also consider implementing network intrusion detection systems specifically configured to identify and alert on SCCP protocol anomalies that could indicate exploitation attempts.