CVE-2026-89106: SAP UI5 Cross-Site Scripting Vulnerability

CVE-2026-89106 Overview

CVE-2026-89106 is an input validation weakness in SAP UI5, the HTML5 user interface framework used across SAP web applications. Under certain configurations, SAP UI5 fails to properly validate user-supplied content before rendering it in a browser context. An authenticated attacker with low privileges can submit crafted content that is later rendered in a victim's browser, producing a cross-site scripting style outcome. The weakness is tracked under [CWE-183] (Permissive List of Allowed Inputs). Exploitation requires user interaction and benefits from a scope change, meaning the injected content can affect resources beyond the vulnerable component.

Critical Impact
An authenticated low-privileged attacker can inject content that executes in another user's browser session, exposing limited confidentiality and integrity data within the SAP UI5 application context.

Affected Products

SAP UI5 framework (specific supported versions as listed in SAP Note #3799054)
SAP web applications built on vulnerable SAP UI5 releases
SAP Fiori-based front-ends consuming the affected UI5 libraries

Discovery Timeline

2026-10-13 - CVE-2026-89106 published to the National Vulnerability Database (NVD)
2026-10-15 - Last updated in NVD database

Technical Details for CVE-2026-89106

Vulnerability Analysis

SAP UI5 renders dynamic content supplied by application users across data-binding expressions, control properties, and HTML containers. When specific configurations are enabled, the framework accepts input that should be filtered or encoded before being emitted into the Document Object Model. An attacker who can submit content through a legitimate application function, such as a form, comment field, or custom property, can embed script-bearing payloads. The payload executes when a second user loads the view containing the stored data. Because the exploit crosses user boundaries within the browser, the CVSS vector reflects a scope change, with limited impact on confidentiality and integrity and no availability impact.

Root Cause

The root cause is permissive input handling in SAP UI5 rendering paths governed by [CWE-183]. Under the affected configurations, the framework treats classes of input as allowed when they should be rejected or neutralized. Output encoding routines do not consistently sanitize the data before it reaches the browser.

Attack Vector

The attack is remote and network-based but requires an authenticated session with low privileges and user interaction from the victim. The attacker stores or reflects malicious content through an SAP UI5 input surface. When a victim renders the affected view, their browser executes the injected content under the application origin. See SAP Note #3799054 for the authoritative component and configuration list.

// No verified public proof-of-concept code is available for CVE-2026-89106.
// Refer to SAP Note #3799054 for configuration details and affected code paths.

Detection Methods for CVE-2026-89106

Indicators of Compromise

HTTP request bodies or query parameters containing <script>, javascript:, or event handler attributes submitted to SAP UI5 endpoints
Stored SAP application fields containing encoded or obfuscated HTML fragments that reappear in UI5 rendered views
Browser console errors or unexpected outbound requests originating from SAP Fiori launchpad sessions

Detection Strategies

Inspect web application firewall (WAF) and reverse proxy logs for payloads targeting SAP UI5 OData services and form POST endpoints
Correlate low-privileged user accounts creating or editing content with subsequent anomalous browser activity from administrator sessions
Review Content Security Policy (CSP) violation reports from SAP front-ends for inline script or event handler blocks

Monitoring Recommendations

Enable verbose request logging on SAP Gateway and NetWeaver front-end components that serve UI5 content
Forward SAP audit and web dispatcher logs to a centralized analytics platform for cross-session correlation
Alert on repeated input validation failures or encoding errors emitted by SAP UI5 server-side renderers

How to Mitigate CVE-2026-89106

Immediate Actions Required

Apply the SAP UI5 patches referenced in SAP Note #3799054 during the next SAP Security Patch Day cycle
Audit SAP UI5 application configurations for options that disable or relax default output encoding
Restrict content authoring privileges to the minimum set of accounts required for business operations

Patch Information

SAP has released a corrective note on SAP Security Patch Day. Administrators should download and apply the fixes listed in SAP Note #3799054 and verify applicability through the SAP Security Patch Day Announcement. Patch deployment should follow standard SAP transport and regression testing procedures.

Workarounds

Enable strict Content Security Policy headers on SAP Fiori launchpad and custom UI5 applications to block inline script execution
Enforce server-side HTML sanitization on all user-controllable fields rendered by SAP UI5 controls
Disable optional UI5 configuration flags that permit raw HTML in control properties until patching is complete

bash

# Example Content Security Policy header for SAP UI5 front-ends
add_header Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'; frame-ancestors 'self'";