What is the CVSS score of CVE-2026-20091?

CVE-2026-20091 has a CVSS 3.1 base score of 4.8 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N. EPSS exploitation probability: 0.0%.

Which versions of Cisco are affected by CVE-2026-20091?

CVE-2026-20091 presents moderate security risk, a cross-site scripting vulnerability rated CVSS 4.8. Attackers could inject scripts to steal sessions or perform actions as authenticated users.

How to fix or mitigate CVE-2026-20091?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Verify Content-Security-Policy and output encoding.

Cisco CVE-2026-20091

MEDIUM

Cross-site Scripting (XSS) (CWE-79)

2026-02-25 psirt@cisco.com

Cisco XSS

4.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

4.8 MEDIUM

AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 21:55 vuln.today

CVE Published

Feb 25, 2026 - 17:25 nvd

MEDIUM 4.8

DescriptionCVE.org

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. 

AnalysisAI

web-based management interface of Cisco FXOS Software and Cisco UCS Manager Software is affected by cross-site scripting (xss) (CVSS 4.8).

Technical ContextAI

This vulnerability (CWE-79: Cross-site Scripting (XSS)) exists in the web-based management component. 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.

Affected ProductsAI

Product: web-based management interface of Cisco FXOS Software and Cisco UCS Manager Software. Component: web-based management.

RemediationAI

Monitor vendor advisories for a patch. Implement output encoding and Content Security Policy headers. Restrict network access to the affected service where possible.