A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct directory traversal attacks and obtain read and delete access to sensitive files on a targeted system. The vulnerability is due to a lack of proper input validation of the HTTP URL. An attacker could exploit this vulnerability by sending a crafted HTTP request containing directory traversal character sequences. An exploit could allow the attacker to view or delete arbitrary files on the targeted system. When the device is reloaded after exploitation of this vulnerability, any files that were deleted are restored. The attacker can only view and delete files within the web services file system. This file system is enabled when the affected device is configured with either WebVPN or AnyConnect features. This vulnerability can not be used to obtain access to ASA or FTD system files or underlying operating system (OS) files. Reloading the affected device will restore all files within the web services file system.
Use CWE-22, Cisco vendor hub and Firepower Threat Defense product page to widen CVE-2020-3187 into its surrounding weakness, vendor, and product context.
Compare it with CVE-2025-20333, CVE-2025-20362 and CVE-2024-20412 for nearby disclosures in the same product family. Additional editorial context is available in Weekly Security Roundup: Navigating the April 2026 Threat Landscape and Critical Framework Exploits.