CVE-2026-20047

XSS in Cisco Identity Services Engine ≤ 3.2

XSS

Published

15 January 2026

Modified

30 January 2026

Patch / advisory

View advisory

CVSS Score v3.1 4.8

Click a component to see what it means

Raw vector

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

EPSS Score 0.0024 15th percentile

Risk Priority 33 floored blend · peak EPSS

Summary

CVE-2026-20047 is a medium-severity Basic XSS (CWE-80) vulnerability in Cisco Identity Services Engine. Its CVSS base score is 4.8 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Content Injection (T1659); ranked at the 15th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2026-2741

Vulnerability Data

A vulnerability in the web-based management interface of Cisco Identity Services Engine (ISE) and Cisco ISE Passive Identity Connector (ISE-PIC) could allow an authenticated, remote attacker to conduct cross-site scripting (XSS) attacks 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 code 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 administrative credentials.

CWE(s): CWE-80

Related Threats

MITRE ATT&CK Enterprise Techniques

T1659 Content Injection Initial Access

Adversaries may gain access and continuously communicate with victims by injecting malicious content into systems through online network traffic.

attack.mitre.org →

T1539 Steal Web Session Cookie Credential Access

An adversary may steal web application or service session cookies and use them to gain access to web applications or Internet services as an authenticated user without needing credentials.

attack.mitre.org →

T1189 Drive-by Compromise Initial Access

Adversaries may gain access to a system through a user visiting a website over the normal course of browsing.

attack.mitre.org →

Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-20267Same product: Cisco Identity Services Engine

CVE-2026-20076Same product: Cisco Identity Services Engine

CVE-2024-20525Same product: Cisco Identity Services Engine

CVE-2024-20539Same product: Cisco Identity Services Engine

CVE-2025-20304Same product: Cisco Identity Services Engine

CVE-2025-20289Same product: Cisco Identity Services Engine

CVE-2024-20443Same product: Cisco Identity Services Engine

CVE-2023-20208Same product: Cisco Identity Services Engine

CVE-2025-20205Same product: Cisco Identity Services Engine

CVE-2025-20303Same product: Cisco Identity Services Engine

Affected Assets

cisco

identity services engine

3.2.0, 3.3.0, 3.4.0 · ≤ 3.2

Mitigating Controls

Control response

Prevent

Stop it (NIST 800-53)

—

Detect

Catch it (NIST detect / respond)

—

Harden

Shrink the surface (DISA STIG)

—

Validate

Prove the fix (OWASP ASVS)

V1.2.1
V1.3.1
V1.3.3
V1.3.4

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation can discover missing or incorrect neutralization of script tags through targeted XSS test cases.

SI-10 Information Input Validation good match

Input validation explicitly requires checking and neutralizing untrusted web inputs containing script-related characters before they reach a downstream renderer.

SA-8 Security and Privacy Engineering Principles partial match

Secure engineering principles include mandatory output encoding and neutralization of HTML metacharacters to stop injection at the source.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match

prevents

Secure SDLC practices directly require output encoding and input validation that prevent basic XSS.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match

finds

Security testing in development catches unneutralized script tags before release.

A.8.25 Secure development life cycle partial match

prevents

Secure SDLC mandates input validation and output encoding that directly prevent basic XSS.

A.8.26 Application security requirements partial match

prevents

Application security requirements explicitly call for neutralization of script-related HTML tags.

A.8.28 Secure coding partial match

prevents

Secure coding standards require proper escaping of <, >, & to block XSS.