CVE-2026-20091: Cisco Firepower Extensible Operating System Fxos

Medium severity, CVSS 4.8. EPSS: 0.2% chance of exploitation in the next 30 days.

A vulnerability in the web-based management interface of Cisco FXOS Software and Cisco UCS Manager Software could allow an authenticated, remote attacker to conduct a stored cross-site scripting (XSS) attack against a user of the interface. This vulnerability is due to insufficient validation of user-supplied input by the web-based management interface of an affected system. An attacker could exploit this vulnerability by injecting malicious data into specific pages of 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. To exploit this vulnerability, the attacker must have valid credentials for a user account with the role of Administrator or AAA Administrator. 

Affected products

• Cisco Cisco Firepower Extensible Operating System Fxos: version 2.14.1.131 only; version 2.14.1.143 only; version 2.14.1.163 only; version 2.14.1.167 only; version 2.16.0.128 only
• Cisco Cisco Secure Firewall Adaptive Security Appliance ASA Software: version 9.12.2 only; version 9.12.1 only; version 9.12.3 only; version 9.12.4 only; version 9.12.3.2 only; version 9.12.3.12 only; …
• Cisco Cisco Unified Computing System Managed: version 4.0(4h) only; version 4.1(1a) only; version 4.0(1c) only; version 4.0(4a) only; version 4.0(1a) only; version 4.0(1d) only; …

Published 2026-02-25. Last modified 2026-06-17.