CVE-2020-3420 in Unified Communications Manager
Summary
by MITRE • 11/18/2024
A vulnerability in the web-based management interface of Cisco Unified Communications Manager (Unified CM) and Cisco Unified Communications Manager Session Management Edition (Unified CM SME) could allow an authenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the interface. The vulnerability is due to insufficient validation of user-supplied input by the web-based management interface of the affected software. An attacker could exploit this vulnerability by inserting malicious data into a specific data field in the interface. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive browser-based information.There are no workarounds that address this vulnerability.
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Analysis
by VulDB Data Team • 08/06/2025
The vulnerability identified as CVE-2020-3420 represents a critical cross-site scripting flaw within the web-based management interface of Cisco Unified Communications Manager and Unified Communications Manager Session Management Edition products. This weakness stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied data before processing within the application's web interface. The vulnerability affects organizations that rely on these communication platforms for their enterprise voice and video infrastructure, potentially exposing critical business communications systems to unauthorized access and manipulation.
The technical exploitation of this vulnerability requires an authenticated attacker who can leverage the insufficient input validation to inject malicious scripts into specific data fields within the management interface. This type of attack falls under the common weakness enumeration CWE-79 which specifically addresses cross-site scripting vulnerabilities where applications fail to properly validate or escape user input before rendering it in web pages. The attack vector operates through the web interface itself, meaning that successful exploitation could enable attackers to execute arbitrary code within the browser context of authenticated users who interact with the vulnerable interface.
The operational impact of this vulnerability extends beyond simple script execution capabilities, as it could potentially allow attackers to access sensitive browser-based information and manipulate the management interface in ways that compromise the integrity of the entire communication system. Attackers could leverage this vulnerability to perform session hijacking, steal user credentials, or gain unauthorized access to critical system configuration data. The lack of available workarounds means that organizations cannot implement temporary mitigations while awaiting official patches, leaving them vulnerable until proper security updates are deployed.
Organizations affected by CVE-2020-3420 should prioritize immediate remediation through official Cisco security advisories and patch management procedures. The vulnerability aligns with ATT&CK technique T1059.007 which covers scripting through web shells, and represents a significant risk to enterprise communication infrastructure. Security teams should implement network segmentation to limit access to the management interfaces, enforce strict authentication controls, and monitor for suspicious activities in the web-based management systems. Additionally, regular security assessments should verify that all Cisco Unified Communications Manager installations have been properly updated to address this specific XSS vulnerability and prevent potential exploitation by threat actors targeting enterprise communication platforms.