CVE-2025-53096 identifies a medium-severity vulnerability in LizardByte's Sunshine, a self-hosted game streaming server compatible with Moonlight clients. The vulnerability stems from improper restriction of rendered UI layers or frames (CWE-1021), specifically a lack of protection against Clickjacking attacks in the Sunshine web user interface prior to version 2025.628.4510. Clickjacking occurs when an attacker embeds a legitimate web interface within an invisible or disguised iframe on a malicious website. When an authenticated user interacts with this malicious page, their clicks may be hijacked to perform unintended actions within the Sunshine application without their knowledge or consent. This can lead to unauthorized manipulation of the streaming server's settings or operations. The vulnerability requires user interaction (clicks) but no prior authentication bypass or elevated privileges, as the user must already be authenticated to Sunshine. The CVSS 3.1 base score is 5.4 (medium), reflecting network attack vector, low attack complexity, no privileges required, but user interaction needed, and impacts on integrity and availability but not confidentiality. No known exploits in the wild have been reported as of publication. The issue was addressed in Sunshine version 2025.628.4510 by implementing appropriate frame-busting or X-Frame-Options headers to prevent embedding in iframes, thereby mitigating clickjacking risks.

For European organizations using Sunshine as a self-hosted game streaming solution, this vulnerability could allow attackers to trick authenticated users into unknowingly executing actions that may disrupt streaming services or alter configurations, potentially causing denial of service or degraded user experience. Although the impact on confidentiality is minimal, integrity and availability of the streaming service can be compromised. This could affect gaming cafes, esports organizations, or enterprises leveraging Sunshine for remote game streaming. The risk is heightened in environments where users access the Sunshine web UI from browsers without additional security controls or awareness of clickjacking threats. However, since exploitation requires user interaction and authentication, the threat is somewhat limited to targeted social engineering attacks rather than widespread automated exploitation. The lack of known exploits reduces immediate risk but does not eliminate the potential for future attacks, especially as the vulnerability is publicly disclosed.

European organizations should promptly update Sunshine installations to version 2025.628.4510 or later, where the vulnerability is patched. In addition, administrators should implement Content Security Policy (CSP) frame-ancestors directives to restrict which domains can embed the Sunshine UI, further reducing clickjacking risks. User education is critical: training users to recognize suspicious websites and avoid interacting with unknown or untrusted links while authenticated can reduce successful social engineering attempts. Network-level protections such as web application firewalls (WAFs) can be configured to detect and block suspicious iframe embedding or unusual HTTP headers. Monitoring user activity logs for anomalous actions during sessions may help detect exploitation attempts. Finally, organizations should consider isolating the Sunshine web UI behind VPNs or internal networks to limit exposure to external threats.