CVE-2026-66771 in SAPUI5
Summary
by MITRE • 08/11/2026
SAPUI5 allows a key user with content adaptation privileges to inject malicious script content into persisted application changes. When another user subsequently opens the adapted application, the injected script executes in the victim's browser session. Successful exploitation could allow the attacker to access sensitive session data and perform unauthorized actions on behalf of the victim, resulting in a high impact on confidentiality and integrity. There is no impact on availability.
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Analysis
by VulDB Data Team • 08/11/2026
This vulnerability represents a critical cross-site scripting flaw within SAPUI5 applications that leverages privileged user permissions to execute malicious code against other users. The security weakness stems from insufficient input validation and sanitization mechanisms when processing content adaptation modifications, allowing a key user with appropriate privileges to inject arbitrary script code into application configurations that persist beyond the initial modification session.
The technical exploitation occurs through the content adaptation feature which enables authorized users to customize application interfaces and behaviors. When a malicious key user inputs crafted script content into these editable fields, the system fails to properly sanitize or escape the input before storing it in persistent application data structures. The vulnerability specifically targets the rendering process where adapted content is subsequently served to other users who access the modified application interface.
The operational impact of this vulnerability extends beyond simple script execution as it creates a persistent backdoor for attackers who can leverage the compromised user sessions to extract sensitive session tokens, cookies, and authentication credentials. This allows for unauthorized access to protected resources, data exfiltration, and potential lateral movement within the SAP ecosystem. The attack vector operates through standard web browser mechanisms where the injected script executes in the context of legitimate user sessions, making detection particularly challenging.
The vulnerability aligns with CWE-79 Cross-Site Scripting and follows ATT&CK technique T1566 Phishing with Malicious Attachments or Links, though in this case the malicious payload is delivered through application content adaptation rather than traditional email vectors. The attack chain involves privilege escalation through legitimate key user accounts followed by session hijacking and data manipulation. Organizations may face significant compliance implications due to potential data breaches affecting customer information, financial records, and proprietary business data.
Mitigation strategies should include implementing comprehensive input validation and output encoding mechanisms for all user-modifiable content within SAPUI5 applications. The system should enforce strict sanitization of adaptation inputs using established security libraries and frameworks while maintaining role-based access controls to limit who can perform content modifications. Regular security assessments and code reviews should specifically target the content adaptation features and related data persistence mechanisms. Additionally, implementing Content Security Policy headers and browser-based protections can provide additional defense-in-depth measures against script execution. Organizations must also establish monitoring procedures to detect anomalous content modification patterns that could indicate malicious activity within their SAP environments.