CVE-2026-26050: RICOH Job Log Tool DLL Hijacking Vulnerability

CVE-2026-26050 Overview

CVE-2026-26050 is a DLL hijacking vulnerability affecting the installer for RICOH Job Log Aggregation/Analysis Software (ジョブログ集計/分析ソフトウェア RICOHジョブログ集計ツール). The vulnerability exists due to an insecure DLL search path issue in the installer component, which allows attackers to execute arbitrary code with administrative privileges when a user runs the vulnerable installer in a directory containing a malicious DLL file.

Critical Impact

Successful exploitation allows arbitrary code execution with administrative privileges, potentially leading to complete system compromise during software installation.

Affected Products

• RICOH Job Log Aggregation Tool (RICOHジョブログ集計ツール) versions prior to Ver.1.3.7
• Installer components for the affected software versions

Discovery Timeline

• 2026-02-20 - CVE-2026-26050 published to NVD
• 2026-02-20 - Last updated in NVD database

Technical Details for CVE-2026-26050

Vulnerability Analysis

This vulnerability is classified under CWE-427 (Uncontrolled Search Path Element), which describes a condition where an application searches for critical resources using an externally-supplied search path that can be compromised by malicious actors.

The RICOH Job Log Aggregation Tool installer fails to properly control the DLL search path during execution. When the installer runs, Windows follows a specific search order to locate required DLL files. If the installer does not explicitly specify the full path to required DLLs, Windows may load a malicious DLL from the current working directory or other locations in the search path before finding the legitimate system DLL.

This type of vulnerability requires local access and user interaction—specifically, a victim must execute the installer from a directory where an attacker has placed a crafted malicious DLL file. Common attack scenarios include placing the installer alongside malicious DLLs in user-writable directories such as the Downloads folder.

Root Cause

The root cause is an insecure DLL search path configuration in the installer executable. The installer does not use secure DLL loading practices such as:

• Specifying absolute paths for DLL loading
• Using the SetDllDirectory("") API to remove the current directory from the search path
• Implementing DLL Safe Search Mode properly

This allows the Windows loader to search for and potentially load malicious DLLs from untrusted locations before locating the legitimate system libraries.

Attack Vector

The attack requires local access and follows this general pattern:

1. An attacker places a malicious DLL with a specific name (matching a DLL the installer attempts to load) in a location the victim will use
2. The victim downloads or copies the legitimate RICOH installer to the same directory (e.g., Downloads folder)
3. When the victim executes the installer, Windows searches for required DLLs
4. The malicious DLL is found first and loaded into the installer process
5. The malicious code executes with the same privileges as the installer (typically administrative privileges during installation)

The vulnerability requires user interaction (running the installer) but no authentication, making it exploitable through social engineering tactics such as distributing installers alongside malicious DLLs in compressed archives.

Detection Methods for CVE-2026-26050

Indicators of Compromise

• Unexpected DLL files present in user-writable directories alongside installer executables
• Process execution logs showing DLLs loaded from non-standard paths during RICOH software installation
• Unusual child processes spawned from installer executables
• Modified or suspicious DLL files in download directories with common hijackable names

Detection Strategies

• Monitor for DLL loading events from user-writable directories during software installation processes
• Implement application whitelisting to prevent unauthorized DLL execution
• Use endpoint detection and response (EDR) solutions to identify suspicious DLL side-loading behavior
• Audit file creation events in common download and temporary directories for DLL files

Monitoring Recommendations

• Enable Windows Security Event logging for DLL load events (Event ID 7045, Sysmon Event ID 7)
• Configure alerts for installer processes loading DLLs from non-system paths
• Monitor for creation of DLL files in user profile directories that match common hijackable DLL names
• Implement file integrity monitoring on critical installation directories

How to Mitigate CVE-2026-26050

Immediate Actions Required

• Upgrade to RICOH Job Log Aggregation Tool version 1.3.7 or later immediately
• Verify installers are downloaded only from official RICOH sources
• Run installers from clean, dedicated directories rather than the Downloads folder
• Scan installer directories for unexpected DLL files before execution

Patch Information

RICOH has released version 1.3.7 of the Job Log Aggregation Tool which addresses this vulnerability. The update is available through the official RICOH support portal. Users should download the patched installer from the Ricoh Firmware Update History page and verify the integrity of downloaded files before installation.

Additional technical details are available in the JVN #69531868 Advisory.

Workarounds

• Create a dedicated, clean directory for running installers and ensure no unexpected DLL files are present
• Run installers with the minimum necessary privileges when possible
• Use application control solutions to block DLL execution from user-writable directories
• Implement Group Policy to enable Safe DLL Search Mode across the organization

# Configuration example
# Enable Safe DLL Search Mode via Windows Registry
# This removes the current directory from the DLL search path
reg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager" /v SafeDllSearchMode /t REG_DWORD /d 1 /f

# Verify the setting
reg query "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager" /v SafeDllSearchMode