CVE-2025-26861 Overview
CVE-2025-26861 affects the RemoteCall Remote Support Program (Operator client) in versions prior to 5.3.0. The product loads dynamic-link libraries from an uncontrolled search path [CWE-427]. An attacker who places a crafted DLL in the same directory as the affected executable can trigger arbitrary code execution when the operator launches the application. The flaw requires local access and user interaction, but it executes code in the security context of the launching user. RemoteCall is a remote support tool used by support technicians, making the Operator client a high-value target for staged DLL planting attacks.
Critical Impact
Arbitrary code execution in the context of the RemoteCall operator when a malicious DLL is sideloaded from the application directory.
Affected Products
- RemoteCall Remote Support Program (for Operator) versions prior to 5.3.0
- Operator client installations on Windows endpoints
- Any deployment that places the application binary in a user-writable directory
Discovery Timeline
- 2025-10-15 - CVE-2025-26861 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-26861
Vulnerability Analysis
The RemoteCall Operator client resolves one or more DLL dependencies using an uncontrolled search path. On Windows, the loader searches the application directory before most system locations when locating a named DLL. If a DLL with a matching name exists in the same folder as the RemoteCall executable, the loader maps and executes it inside the process. Attackers exploit this by dropping a crafted DLL alongside the binary, often using filenames the application is known to load. When the operator next starts the program, the malicious library is loaded and its DllMain runs with the operator's privileges. The vendor classifies the issue as CWE-427: Uncontrolled Search Path Element.
Root Cause
The application does not pin DLL loads to known directories using mechanisms such as LoadLibraryEx with LOAD_LIBRARY_SEARCH_SYSTEM32 or a fully qualified path. It also does not validate signatures on loaded modules. As a result, the standard Windows DLL search order resolves attacker-controlled files from the current working directory or the application install path before legitimate copies.
Attack Vector
Exploitation requires local file placement and user interaction. An attacker drops a malicious DLL into the directory containing the RemoteCall Operator binary, then waits for or induces the operator to launch the application. The DLL executes immediately on load. Delivery paths include shared download folders, USB media, archive extraction that preserves a payload alongside the executable, or compromise of a user-writable install location.
No verified public exploit code is available. The vulnerability mechanism is described in the JVN Vulnerability Report.
Detection Methods for CVE-2025-26861
Indicators of Compromise
- Unsigned or unexpected DLL files present in the RemoteCall Operator installation directory
- DLL files in the application folder with modification timestamps that do not match the installer
- RemoteCall Operator process loading modules from non-standard paths outside System32 or the verified install directory
- Child processes spawned by the RemoteCall Operator executable shortly after launch that do not correspond to normal remote support activity
Detection Strategies
- Monitor image-load events (Sysmon Event ID 7) for the RemoteCall Operator process and alert on unsigned DLLs loaded from the application directory
- Baseline the legitimate set of DLLs shipped in version 5.3.0 and flag deviations
- Hunt for write operations to the RemoteCall install directory by processes other than the official installer or update service
Monitoring Recommendations
- Forward process creation, image load, and file create events from Windows endpoints to a central analytics platform
- Apply YARA or hash-based allowlists to DLLs in the RemoteCall directory
- Audit endpoints periodically for RemoteCall Operator versions below 5.3.0
How to Mitigate CVE-2025-26861
Immediate Actions Required
- Upgrade all RemoteCall Operator installations to version 5.3.0 or later using the RemoteCall Software Download page
- Inventory endpoints running the Operator client and prioritize remediation for support technicians and privileged users
- Inspect existing RemoteCall install directories for foreign or unsigned DLLs and remove any that are not part of the official distribution
Patch Information
The vendor addresses CVE-2025-26861 in RemoteCall Remote Support Program version 5.3.0. Refer to the JVN Vulnerability Report for vendor coordination details and obtain the fixed installer from the official RemoteCall download site.
Workarounds
- Install the RemoteCall Operator client only in directories protected from write access by standard users, such as C:\Program Files
- Restrict write permissions on the application directory to administrators using NTFS access control lists
- Apply application allowlisting (for example, Windows Defender Application Control or AppLocker) to block execution of unsigned DLLs from user-writable paths
- Educate support staff to launch RemoteCall only from the verified install location and not from downloads, archives, or removable media
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
