CVE-2026-8049 Overview
CVE-2026-8049 affects SignalRGB versions prior to 1.3.7.0. The \\.\SignalIo device object is created without an explicit Security Descriptor Definition Language (SDDL) string and without the FILE_DEVICE_SECURE_OPEN characteristic. This produces overly permissive default access control on the device object. Any authenticated local user can open a handle to the driver and issue privileged I/O control codes (IOCTLs). The flaw exposes kernel-mode functionality intended for the SignalRGB service to unprivileged callers. Exploitation enables local privilege escalation paths that depend on the IOCTLs the driver exposes.
Critical Impact
Any authenticated local user can obtain a handle to the \\.\SignalIo device and invoke privileged IOCTLs, providing a foothold for local privilege escalation.
Affected Products
- SignalRGB versions prior to 1.3.7.0
- The \\.\SignalIo kernel device object
- Windows endpoints running vulnerable SignalRGB installations
Discovery Timeline
- 2026-06-17 - CVE-2026-8049 published to the National Vulnerability Database (NVD)
- 2026-06-17 - Last updated in NVD database
- Reference - CERT Vulnerability Advisory #380058
Technical Details for CVE-2026-8049
Vulnerability Analysis
The SignalRGB driver registers a control device named \\.\SignalIo to receive IOCTL requests from the user-mode service. When a Windows driver calls IoCreateDevice without supplying an SDDL string through IoCreateDeviceSecure or an INF directive, the device object inherits a default security descriptor. That default permits handle access to all authenticated users on the system. The driver also omits the FILE_DEVICE_SECURE_OPEN device characteristic. Without FILE_DEVICE_SECURE_OPEN, the I/O Manager skips applying the device's security descriptor to namespace opens. Together, these omissions expose the driver's IOCTL interface to any logged-on user.
Root Cause
The root cause is an insecure default configuration combined with missing access control hardening on a kernel device object. The driver author did not declare a restrictive SDDL during device creation and did not set the FILE_DEVICE_SECURE_OPEN flag. The result is an Insecure Permissions defect on a privileged kernel interface. The advisory does not enumerate the individual IOCTLs, but their accessibility to non-administrators removes the trust boundary the driver was expected to enforce.
Attack Vector
Exploitation requires local access with an authenticated user session. An attacker calls CreateFileW on \\\\.\\SignalIo to obtain a handle, then invokes DeviceIoControl with IOCTLs exposed by the driver. Because the device grants access to standard users, no elevation, token manipulation, or driver loading is required. The attacker leverages the driver's existing kernel-mode privileges to perform actions reserved for the SignalRGB service. Refer to CERT Vulnerability Advisory #380058 for further technical context.
Detection Methods for CVE-2026-8049
Indicators of Compromise
- Unexpected processes opening handles to \\.\SignalIo outside of the SignalRGB service binary.
- DeviceIoControl calls to the SignalRGB driver originating from user shells, scripting hosts, or non-standard binaries.
- New child processes or token changes spawned shortly after non-service interactions with the driver.
Detection Strategies
- Inventory installed SignalRGB versions and flag any host running a version earlier than 1.3.7.0.
- Hunt for image loads of the SignalRGB kernel driver paired with handle opens from non-vendor processes.
- Build behavioral rules that correlate CreateFile on \\.\SignalIo with subsequent privilege changes in the calling process tree.
Monitoring Recommendations
- Enable Windows kernel object access auditing on third-party driver device objects where supported.
- Forward Sysmon Event ID 1 (process creation) and EDR file-object telemetry to a central data lake for retrospective hunting.
- Alert on driver IOCTL activity initiated by interactive user sessions rather than the SignalRGB service account.
How to Mitigate CVE-2026-8049
Immediate Actions Required
- Upgrade SignalRGB to version 1.3.7.0 or later on all affected endpoints.
- Restrict local logon to trusted users on systems that cannot be patched immediately.
- Audit endpoints for SignalRGB installations that were deployed outside standard software management channels.
Patch Information
The vendor addressed the issue in SignalRGB 1.3.7.0. The fix introduces an explicit SDDL security descriptor on the \\.\SignalIo device object and sets the FILE_DEVICE_SECURE_OPEN characteristic during device creation. Upgrading replaces the vulnerable driver and enforces access control checks against the device's security descriptor. Consult CERT Vulnerability Advisory #380058 for vendor coordination details.
Workarounds
- Uninstall SignalRGB on endpoints that do not require RGB peripheral control until the patched build is deployed.
- Stop and disable the SignalRGB service and unload the driver where uninstalling is not feasible.
- Apply application allowlisting to block execution of unauthorized binaries that could interact with \\.\SignalIo.
# Verify the installed SignalRGB version on Windows endpoints
Get-ItemProperty "HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\*" |
Where-Object { $_.DisplayName -like "SignalRGB*" } |
Select-Object DisplayName, DisplayVersion, InstallLocation
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
