CVE-2026-34558: CI4MS: Methods Management Full Account Takeover for All-Roles & Privilege-Escalation via Stored DOM XSS
The application fails to properly sanitize user-controlled input within the Methods Management functionality when creating or managing application methods/pages. Multiple input fields accept attacker-controlled JavaScript payloads that are stored server-side without sanitization or output encoding.
These stored values are later rendered directly into administrative interfaces and global navigation components without proper encoding, resulting in Stored DOM-Based Cross-Site Scripting (XSS).
Critically, because created methods are automatically rendered inside the system’s navigation/menu structure, the injected payload executes globally — meaning every page visited where the malicious method appears in the menu triggers the XSS payload automatically.
This significantly increases severity, as exploitation is not limited to a single view — it becomes a platform-wide persistent execution point.
References
Code Behaviors & Features
Detect and mitigate CVE-2026-34558 with GitLab Dependency Scanning
Secure your software supply chain by verifying that all open source dependencies used in your projects contain no disclosed vulnerabilities. Dependency Scanning using SBOM also detects vulnerabilities from proprietary advisories that this site does not include. Learn more about Dependency Scanning using SBOM →