Fuji Monitouch V SFT 6 HMI Vulnerabilities CVE 2025 54496 54526

Fuji Electric’s Monitouch V‑SFT‑6 HMI configuration tool contains multiple memory‑corruption vulnerabilities — including both heap‑ and stack‑based buffer overflows — that can crash engineering workstations and, under certain conditions, enable arbitrary code execution when specially crafted project files are opened; these flaws were disclosed through a CISA advisory and tracked as CVE‑2025‑54496 and CVE‑2025‑54526.

Background​

Fuji Electric’s Monitouch V‑SFT family is a Windows‑hosted human‑machine interface (HMI) configuration tool used to design and deploy screens, logic, and project files to Monitouch operator panels in industrial plants. The affected product in this advisory is identified as Monitouch V‑SFT‑6, with vulnerable builds in the 6.2.x branch identified by the vendor and coordinated in the public advisory. The vulnerabilities were reported by third‑party researchers working with a vulnerability disclosure program and were subsequently published in an ICS advisory.
These advisories are significant because engineering workstations and HMI editors are privileged pivot points inside OT networks: they routinely open supplier or partner project files, push configuration changes to controllers and panels, and often run with elevated access or with credentials that can reconfigure devices. Tools that parse project files therefore represent a high‑value attack surface for adversaries seeking initial access or lateral movement into operational networks.

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Executive summary of the findings​

• A maliciously crafted Monitouch project file can trigger a heap‑based buffer overflow (CVE‑2025‑54496) and a stack‑based buffer overflow (CVE‑2025‑54526) when processed by Monitouch V‑SFT‑6.
• Both CVEs carry high severity ratings: CISA and the public trackers recorded CVSS v3.1 base scores of 7.8 (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) and CVSS v4 base scores of 8.4, reflecting high impact and low attack complexity.
• Exploitation requires an attacker‑controlled file and user interaction (the targeted user must open or import the crafted project file), making the vector local/post‑delivery rather than unauthenticated remote network RCE. However, successful exploitation can produce process crashes or, in the worst case, arbitrary code execution in the context of the logged‑in user.
• Fuji Electric issued fixes in their October release cycle (in the V‑SFT 6.2.8.x series) and recommends upgrading to V‑SFT V6.2.9.0 or newer; operators should prioritize updates after appropriate operational validation. Note: verify the exact vendor patch filename and release notes against Fuji Electric’s product advisory before deploying.

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Vulnerability technical overview​

How the bugs behave​

• Heap‑based buffer overflow (CVE‑2025‑54496): During parsing of key project file sections, an input length was not correctly validated before memory copy operations into a heap‑allocated buffer. A crafted file can overwrite heap structures, trigger process instability, and — when combined with other conditions — enable code execution. The issue was assigned a high severity rating and a CVSS v4 score in the high‑8 range.
• Stack‑based buffer overflow (CVE‑2025‑54526): A separate parsing path copies unbounded data into a stack buffer. Overwriting return addresses or saved registers can lead to a crash or, with precise exploitation techniques and the right memory layout, control‑flow hijacking leading to arbitrary code execution. Modern OS mitigations (ASLR, DEP/SEH protections, Control Flow Guard) raise the bar, but reliable exploitation in certain environments remains feasible.

Attack prerequisites and vectors​

• Delivery vector: A crafted Monitouch project file delivered by email attachment, shared network folder, removable media, or vendor/partner file exchange.
• Required action: A user with access to the HMI engineering tool must open or import the malicious project file (user interaction is essential).
• Privileges: No special privileges are required beyond those of the logged‑in user; thus, attacks execute with the same rights as the engineering operator or technician running V‑SFT.
• Remote exploitation: There is no pre‑auth remote network vector that allows an unauthenticated actor to trigger these overflows; exploitation is a local file‑based (post‑delivery) scenario.

Real‑world exploitability caveats​

• Modern Windows deployment mitigations can complicate exploit development; exploit reliability varies depending on OS version, process hardening, compiler options, and presence of exploitation mitigations.
• However, industrial environments often run long‑lived, untouched images and may lag in applying Windows mitigations or vendor updates, which raises practical risk.
• The human element (trusted file exchanges between contractors and operators) makes these vulnerabilities attractive to targeted threat actors, especially in critical manufacturing contexts.

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Who and what is impacted​

Affected product(s) and versions​

• Affected: Fuji Electric Monitouch V‑SFT‑6 HMI configuration software — specific vulnerable builds in the 6.2.x release line were identified in the advisory.
• Confirmed fixed in vendor releases within the 6.2.8.x branch; vendor recommends upgrading to V‑SFT V6.2.9.0 or later to ensure remediation. Operators must confirm the exact build and SHA‑256 checksums against official vendor release notes before deployment.

Sectors and scale​

• Critical Manufacturing and other industrial sectors that deploy Monitouch HMIs are primary at risk, but any organization that uses the V‑SFT editor on Windows engineering stations is potentially affected.
• Deployment is global; the tool is used in production facilities, utilities, and process plants worldwide, increasing the scope of the risk if unpatched project files circulate.

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Risk evaluation and operational impact​

Short‑term impact​

• Denial of service: Opening a crafted file can crash the V‑SFT process or the host application, halting engineering work and potentially preventing configuration changes.
• Local code execution: If an exploit chain succeeds, attackers can run arbitrary code at the user privilege level of the engineering account — a powerful foothold inside OT environments.

Long‑term operational risk​

• Lateral movement: An attacker who obtains code execution on an engineering workstation may pivot to PLCs, HMIs, or other OT devices using existing management channels, credentials, or push‑to‑device mechanisms.
• Supply‑chain abuse: Compromised third‑party engineering firms or contractors that routinely exchange project files are an attractive distribution vector for such crafted files.
• High‑value targeting: Facilities with weak segmentation, inadequate logging, or engineering workstations used for general browsing/email are at particular risk.

Likelihood and severity​

• The attack complexity is low (no elaborate prerequisites beyond file delivery and user action) and impact is high; therefore, these vulnerabilities rank as high priority for industrial defenders. CISA’s risk framing supports rapid remediation and network hardening at the enterprise level.

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Mitigation and remediation roadmap​

Immediate (0–48 hours)​

• Stop opening untrusted project files: Enforce a temporary policy that engineering workstations must not open project files from unvetted sources until after scanning/validation.
• Isolate engineering workstations: Remove direct internet access and restrict network shares; ensure workstations are on an isolated VLAN with strict firewall rules.
• Harden email and file transfer: Block executable or project file attachments at mail gateways where feasible; require project files to be delivered via approved, scanned repositories.

Short term (48 hours – 14 days)​

• Apply vendor updates: Test and deploy Fuji Electric’s patched V‑SFT release (upgrade to V6.2.9.0 or newer after validation in a controlled test environment). Confirm the vendor release notes and checksum before installation.
• Endpoint detections: Deploy or tune EDR rules to detect suspicious process behavior consistent with memory‑corruption exploitation (unexpected child processes, in‑memory code drops, anomalous loads).
• User guidance: Conduct targeted briefings for engineers and contractors about the risk — especially emphasizing not to open files from unfamiliar senders and validating files via out‑of‑band confirmation.

Medium term (2–12 weeks)​

• Implement allow‑lists for file types: Use application control to allow V‑SFT to open only files from specific, signed sources or approved folders.
• Strengthen network segmentation: Ensure engineering workstations cannot directly access PLC device management ports; require jump hosts and strongly authenticated remote access for device updates.
• Audit and inventory: Identify all hosts running V‑SFT, FRENIC‑Loader, and similar engineering tools; catalog their versions and patch status.

Long term (3–12 months)​

• Secure development lifecycle: Work with vendors and procurement to require secure file parsing and fuzzing evidence in future product releases.
• Third‑party security controls: Require contractors to follow secure transfer protocols and sign files, and to keep engineering tools patched.
• Tabletop exercises: Simulate a compromised engineering workstation scenario to validate incident response, backup/restore, and production safety procedures.

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Detection, monitoring, and incident handling​

• Enable comprehensive logging on engineering workstations and centralize logs to a monitored SIEM.
• Watch for unusual local process crashes of V‑SFT, repeated file import failures, and execution of unsigned binaries from user temp folders.
• If compromise is suspected, disconnect the host, preserve forensic artifacts (memory image if possible), and engage established incident response procedures before restoring production functionality.

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Vendor response and validation​

Fuji Electric coordinated fixes in the V‑SFT 6.2.8.x release cycle and recommended an upgrade path to V6.2.9.0 or newer as the secure baseline; operators must validate the vendor bulletin and the installed build before applying patches in production. The vulnerabilities were reported to national stakeholders and published in an ICS advisory summarizing the technical findings and recommended mitigations.
Independent public trackers and incident summaries of similar HMI‑file parsing issues underline the recurring nature of file‑based parsing bugs in OT tooling and reinforce that remediation must combine both patching and operational controls.

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Critical analysis — strengths and gaps in current guidance​

Strengths in the published guidance​

• The advisory correctly emphasizes patching as the primary mitigation and pairs that technical fix with practical ICS hardening advice: network segmentation, limiting engineering workstation exposure, and social‑engineering defenses.
• The disclosure acknowledges attack prerequisites (user interaction and local file delivery), providing useful operational context for defenders prioritizing mitigations.

Practical gaps and residual risks​

• Patching cadence vs. production constraints: Many industrial sites delay updates due to certification windows or compatibility validation. The advisory’s patching recommendation is necessary, but operators will need robust rollback and test plans to deploy updates safely in production.
• Third‑party distribution channels: Vendor and contractor file exchanges remain a blind spot for many plants. Even with an updated V‑SFT fleet, a compromised contractor could deliver poisoned files to an operator who still uses an older image, or to a different tool with similar parsing logic.
• Exploit telemetry uncertainty: At the time of the advisory, no confirmed in‑the‑wild exploitation was reported; however, threat actors weaponize file‑based vectors quickly. The absence of exploitation reports is not proof of safety and should not delay remediation.

Verification and cross‑checking​

• The core technical claims (CVE assignments, CVSS v3.1 and v4 scores, attack vector = local with user interaction, vendor patch guidance) were cross‑checked against the published advisory and independent incident analyses carried in public ICS trackers and community summaries to avoid reliance on a single feed. Operators should still confirm final patch versions and build numbers on Fuji Electric’s official site prior to deployment.

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Practical checklist for Windows and OT administrators​

• Inventory all hosts that run Monitouch V‑SFT, including version numbers and patch levels.
• Immediately quarantine any hosts that cannot be patched and restrict their network access.
• Patch V‑SFT instances to V6.2.9.0 or newer after validating in a test environment.
• Block untrusted project file types at email gateways and require file delivery via approved, scanned repositories.
• Harden engineering workstations: remove admin rights where feasible, enable EDR, and disable web/email usage on production engineering hosts.
• Implement strict network segmentation and require authenticated jump hosts for device updates.
• Conduct targeted security awareness for engineers and contractors about the dangers of opening unknown project files.

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Conclusion​

The Monitouch V‑SFT‑6 vulnerabilities are a textbook example of how file parsing bugs in engineering tools translate into high operational risk for industrial environments. They combine relatively low exploitation complexity with high impact potential because engineering workstations are privileged, trusted nodes inside OT networks. Operators should treat the advisory with urgency: prioritize vendor patch validation and deployment, isolate and harden engineering workstations, and close procedural gaps around third‑party file exchanges and contractor workflows. While public exploitation was not reported at the time of disclosure, the practical attack surface and historical behavior of threat actors argue strongly for immediate remediation and tighter operational controls.

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Source: CISA Fuji Electric Monitouch V-SFT-6 | CISA