CVE-2026-32925: V-SFT Buffer Overflow Vulnerability

CVE-2026-32925 Overview

CVE-2026-32925 is a stack-based buffer overflow vulnerability affecting Fuji Electric V-SFT versions 6.2.10.0 and prior. The vulnerability exists in the VS6ComFile!CV7BaseMap::WriteV7DataToRom function and can be triggered when a user opens a specially crafted V7 file. Successful exploitation may lead to arbitrary code execution on the affected system.

Critical Impact

A stack-based buffer overflow in V-SFT software could allow attackers to execute arbitrary code by convincing a user to open a malicious V7 file, potentially compromising industrial control systems.

Affected Products

• Fuji Electric V-SFT version 6.2.10.0
• Fuji Electric V-SFT versions prior to 6.2.10.0
• All V-SFT installations processing V7 project files

Discovery Timeline

• 2026-04-01 - CVE-2026-32925 published to NVD
• 2026-04-01 - Last updated in NVD database

Technical Details for CVE-2026-32925

Vulnerability Analysis

This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow). The flaw resides in the VS6ComFile!CV7BaseMap::WriteV7DataToRom function within the V-SFT application. When parsing V7 project files, the application fails to properly validate input data before copying it to a fixed-size stack buffer. This allows an attacker to craft a malicious V7 file that, when opened by a victim, overwrites adjacent stack memory including return addresses and saved registers.

The local attack vector requires user interaction—specifically, the victim must open the malicious V7 file. However, this is a common scenario in industrial environments where engineers regularly share and open project files.

Root Cause

The root cause is insufficient bounds checking in the WriteV7DataToRom function when processing V7 file data. The function allocates a fixed-size buffer on the stack and copies user-controlled data from the V7 file without verifying that the input data length does not exceed the buffer capacity. This classic buffer overflow condition allows attackers to overwrite the function's return address and redirect program execution to attacker-controlled code.

Attack Vector

The attack requires local access and user interaction. An attacker must craft a malicious V7 file and deliver it to a victim through social engineering methods such as email attachments, file-sharing platforms, or compromised network shares. When the victim opens the malicious file using the vulnerable V-SFT application, the buffer overflow is triggered.

The vulnerability manifests in the VS6ComFile!CV7BaseMap::WriteV7DataToRom function during V7 file parsing. For technical details on the specific overflow mechanism, refer to the JVN Vulnerability Report JVNVU90448293 and the Fuji Electric Security Advisory.

Detection Methods for CVE-2026-32925

Indicators of Compromise

• Abnormal process behavior or crashes in V-SFT application when opening V7 files
• Unexpected child processes spawned by V-SFT executable
• V7 files with unusually large or malformed data sections
• Memory access violations or application exceptions logged in Windows Event Viewer

Detection Strategies

• Monitor V-SFT application for abnormal memory usage patterns or process crashes
• Implement file integrity monitoring on directories where V7 project files are stored
• Deploy endpoint detection rules to identify attempts to exploit buffer overflow conditions in V-SFT
• Use application whitelisting to prevent unauthorized executables from running after potential exploitation

Monitoring Recommendations

• Enable detailed application crash logging and forward to SIEM for analysis
• Monitor for suspicious V7 files arriving via email or external file transfers
• Track process creation events from the V-SFT application for anomalous child processes
• Implement network monitoring for unusual outbound connections from systems running V-SFT

How to Mitigate CVE-2026-32925

Immediate Actions Required

• Update V-SFT to the latest patched version as provided by Fuji Electric
• Exercise caution when opening V7 files from untrusted or unknown sources
• Implement network segmentation to isolate systems running V-SFT from general network traffic
• Deploy endpoint protection solutions capable of detecting buffer overflow exploitation attempts

Patch Information

Fuji Electric has released information regarding this vulnerability. Users should consult the Fuji Electric Security Advisory for specific patch details and upgrade instructions. Additional vulnerability details are available from the JVN Vulnerability Report JVNVU90448293.

Workarounds

• Restrict V7 file access to trusted sources only and implement strict file validation procedures
• Run V-SFT in a sandboxed or virtualized environment to contain potential exploitation
• Implement application-level firewalls or host-based intrusion prevention to detect exploitation attempts
• Consider disabling automatic file association for V7 files to prevent accidental execution

# Example: Restrict V7 file handling on Windows systems
# Disable auto-open for V7 files via registry (run as Administrator)
reg add "HKEY_CLASSES_ROOT\.v7" /v "NoOpen" /t REG_SZ /d "" /f

# Enable DEP (Data Execution Prevention) for V-SFT application
# This can help mitigate buffer overflow exploitation
bcdedit /set nx AlwaysOn