CVE-2026-50544 in LuminalShine
Summary
by MITRE • 08/13/2026
NortheBridge/luminalshine is a Sunshine-compatible game stream host for Moonlight. Prior to version 26.05.0-rc4, a latent gap exists on a default install, the file at `src/platform/windows/misc.cpp` lives at `C:\ProgramData\LuminalShine\config\apps.json` and is created by the `SYSTEM` service. Under Windows' default `C:\ProgramData` inheritance, that gives `BUILTIN\Users` only Read+Execute — not writable — so the canonical EoP doesn't actually trigger on a vanilla install. Version 26.05.0-rc4 contains a patch for the issue. As a workaround, use default condition DACLs for `ProgramData`.
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Analysis
by VulDB Data Team • 08/13/2026
The vulnerability in NortheBridge/luminalshine affects a specific privilege escalation vector through improper file permissions within the Windows program data directory structure. This issue exists in versions prior to 26.05.0-rc4 where the applications configuration file located at src/platform/windows/misc.cpp is stored at C:\ProgramData\LuminalShine\config\apps.json and is created by the SYSTEM service. The default Windows inheritance behavior for the C:\ProgramData directory structure creates a security gap that allows local users to potentially exploit this configuration.
The technical flaw stems from the default discretionary access control list (DACL) configuration within Windows' program data directory hierarchy where the BUILTIN\Users group receives only Read+Execute permissions rather than full control. This design prevents direct modification of the apps.json file, which would normally be required for privilege escalation attacks. However, this default configuration creates a latent security gap that can be exploited through alternative means. The vulnerability demonstrates how improper permission modeling in system directories can create unexpected attack surfaces even when the primary target file appears secure.
The operational impact of this vulnerability is significant for systems running affected versions of LuminalShine, as it provides a potential pathway for local users to escalate privileges within the context of the application's security model. While the canonical privilege escalation method does not trigger on vanilla installations due to the inherited permissions, the existence of this gap indicates poor security design practices in the application's default configuration. The vulnerability affects both system administrators and end users who may unknowingly expose their systems to potential exploitation through default installation settings.
Mitigation strategies for this vulnerability include upgrading to version 26.05.0-rc4 which contains the appropriate patch addressing the permission issue. Organizations should implement a comprehensive approach that includes verifying file permissions on all program data directories and ensuring proper DACL configurations are maintained. The recommended workaround of using default condition DACLs for ProgramData provides an effective temporary solution while maintaining system stability. This vulnerability highlights the importance of proper privilege separation and access control implementation in cross-platform applications, particularly those operating within Windows environments where directory inheritance can create unexpected security implications. Security practitioners should consider this issue when evaluating applications that store configuration data in system directories and ensure that default installations follow principle of least privilege configurations.
This vulnerability aligns with CWE-276, which addresses improper file permissions, and represents a specific case of privilege escalation through insecure default configurations. The ATT&CK framework would classify this under privilege escalation techniques where adversaries leverage weak permissions in system directories to gain elevated access. The issue demonstrates how application developers must consider the security implications of their installation defaults and properly configure file permissions to prevent unauthorized modification or access that could lead to system compromise.