CVE-2026-76976: SAP NetWeaver ABAP GUI XSS Vulnerability

CVE-2026-76976 Overview

CVE-2026-76976 is a cross-site scripting (XSS) vulnerability affecting applications built on SAP GUI for HTML running on SAP NetWeaver Application Server ABAP. The flaw stems from insufficient sanitization of user-supplied content in certain application functionality. An authenticated attacker can submit malicious payloads that are later rendered to another user. When the victim interacts with the affected content, the attacker's script executes in the victim's browser session. The weakness is classified under CWE-79.

Critical Impact
Authenticated attackers can inject scripts that execute in a victim's browser context, leading to limited disclosure or tampering of data the victim can access within the SAP NetWeaver AS ABAP application.

Affected Products

SAP GUI for HTML
SAP NetWeaver Application Server ABAP
Applications hosted on SAP NetWeaver AS ABAP that render user-supplied content via SAP GUI for HTML

Discovery Timeline

2026-10-13 - CVE-2026-76976 published to the National Vulnerability Database
2026-10-15 - Last updated in NVD database

Technical Details for CVE-2026-76976

Vulnerability Analysis

The vulnerability is a stored or reflected XSS condition within applications based on SAP GUI for HTML. SAP GUI for HTML renders ABAP transactions and screens through a web interface, translating Dynpro elements into HTML served to the user's browser. Certain functionality accepts user-supplied content without applying sufficient output encoding or sanitization. The unsanitized content is subsequently delivered to another user and interpreted by the browser as active markup. The scope change in the attack vector reflects that executed script can influence resources outside the vulnerable component, typically the authenticated user's browser session.

Root Cause

The root cause is improper neutralization of input during web page generation [CWE-79]. The affected SAP GUI for HTML code paths do not escape HTML metacharacters or script delimiters before embedding user-controlled strings into the rendered response. This allows attacker-supplied HTML or JavaScript to be parsed as code rather than data by the receiving browser.

Attack Vector

Exploitation requires an authenticated attacker with low privileges on the SAP system. The attacker places a crafted payload into a field or parameter processed by the vulnerable functionality. A second authenticated user must then interact with the affected content to trigger execution. Successful exploitation can lead to session misuse, limited data exposure, or integrity impact restricted to resources the victim can access. There is no reported impact on application availability. Exploitation is not known to be occurring in the wild, and no public proof-of-concept has been published. The vulnerability is not listed on the CISA Known Exploited Vulnerabilities catalog.

No verified exploit code is publicly available. Refer to SAP Note #3671819 for vendor-controlled technical details.

Detection Methods for CVE-2026-76976

Indicators of Compromise

Stored field values in ABAP tables or application screens containing <script>, onerror=, onload=, or javascript: sequences supplied by low-privileged users.
SAP Web Dispatcher or ICM access logs showing requests to SAP GUI for HTML endpoints with HTML-encoded or percent-encoded script payloads in form parameters.
Unexpected outbound HTTP requests originating from authenticated user browsers after they open specific SAP transactions.

Detection Strategies

Review SAP Security Audit Log (SM19/SM20) for anomalous input submitted by users with limited roles into transactions exposed via SAP GUI for HTML.
Inspect web traffic to /sap/bc/gui/sap/its/webgui and related ITS paths for payloads containing HTML or script metacharacters.
Correlate authenticated session activity with browser-side telemetry to identify script execution originating from SAP-hosted pages.

Monitoring Recommendations

Enable detailed logging on SAP Internet Communication Framework (ICF) services that expose SAP GUI for HTML.
Forward SAP NetWeaver AS ABAP audit logs and reverse-proxy logs to a centralized analytics platform for pattern matching on XSS indicators.
Alert on repeated submission of HTML control characters by the same low-privilege account to transactions used by higher-privilege users.

How to Mitigate CVE-2026-76976

Immediate Actions Required

Apply the fix referenced in SAP Note #3671819 during the next available maintenance window.
Review access to transactions and applications rendered through SAP GUI for HTML and remove unnecessary authorizations for low-trust users.
Audit ABAP custom code that writes user-supplied strings into HTML output and verify that cl_abap_dyn_prg or equivalent escaping routines are used.

Patch Information

SAP addressed this issue as part of SAP Security Patch Day. Administrators should download and implement the correction instructions from SAP Note #3671819. Additional advisory context is available on the SAP Security Patch Day portal.

Workarounds

Restrict access to vulnerable SAP GUI for HTML transactions through role and authorization object controls until the patch is installed.
Deploy a web application firewall rule in front of SAP Web Dispatcher to block requests containing script metacharacters in parameters that should carry only alphanumeric data.
Enforce a strict Content Security Policy header on SAP-hosted responses to limit inline script execution in user browsers.

bash

# Example WAF signature concept for SAP GUI for HTML endpoints
# Block requests with script tags or JavaScript URI schemes in parameters
SecRule ARGS "@rx (?i)(<script|javascript:|onerror=|onload=)" \
  "id:1026076976,phase:2,deny,status:403,log,\
  msg:'Potential XSS targeting SAP GUI for HTML (CVE-2026-76976)'"