CVE Alert: CVE-2025-40772 – Siemens – SiPass integrated

Risk verdict

High-severity stored XSS in the web application could enable session theft and user impersonation; exploitation is not currently indicated as active per SSVC data.

Why this matters

Successful abuse allows an attacker to hijack legitimate sessions and access privileges within the application, potentially compromising facilities access or admin-level functions. The impact can extend to undermining authentication controls and enabling broader access across integrated systems.

Most likely attack path

Attacker must be on an adjacent network segment and rely on user interaction (e.g., a user loading a malicious page), with low attack complexity. Because the flaw is stored XSS, the attacker can inject payloads that persist across sessions and can impersonate other users, potentially enabling privilege‑escalation within the app. Scope remains unchanged, so impact is largely contained to the affected application and its user base.

Who is most exposed

Organisations with internal-facing portals or web interfaces to the system, especially where the server is reachable from the corporate network or facility management networks. deployments on standard LAN/WAN segments without strong input sanitisation are typical risk patterns.

Detection ideas

• Anomalous or repeated session-creation or session-hijack indicators tied to specific user pages.
• Web logs showing suspicious payloads or script execution attempts on authentication/session pages.
• Unusual token or cookie behaviour following user interactions with the web interface.
• WAF or IDS alerts for reflected or stored XSS payload patterns.
• Sudden spikes in user-reported session-related issues or account impersonation events.

Mitigation and prioritisation

• Apply the vendor patch to move beyond V3.0 as soon as feasible.
• If patching is delayed, implement WAF rules to block common XSS payloads and enforce strict input validation/output encoding; enable CSP where possible.
• Harden session management: rotate tokens, enforce secure/HttpOnly cookies, reduce session lifetimes where appropriate.
• Plan for staged rollout with testing in a dev/staging environment; coordinate with change-management and notify users of potential impact.
• If KEV were confirmed or EPSS ≥0.5, treat as priority 1; currently, no such indicators are present.