CVE-2026-57262 Overview
CVE-2026-57262 affects Siemens LOGO! Soft Comfort in all versions prior to V9. The application uses a static, hardcoded Advanced Encryption Standard (AES) master key to encrypt project files. A local attacker can extract this key from the application binaries or process memory. With the key, the attacker can decrypt protected project files or strip project passwords entirely, bypassing the user-defined password protection. The weakness is tracked as Use of Hard-coded Cryptographic Key [CWE-321].
Critical Impact
An attacker with local access to LOGO! Soft Comfort files can recover or remove project passwords without knowing the original credentials, exposing programmable logic controller (PLC) project intellectual property and configuration.
Affected Products
- Siemens LOGO! Soft Comfort — all versions prior to V9
Discovery Timeline
- 2026-08-11 - CVE-2026-57262 published to the National Vulnerability Database (NVD)
- 2026-08-12 - Last updated in NVD database
Technical Details for CVE-2026-57262
Vulnerability Analysis
LOGO! Soft Comfort is the engineering software used to program Siemens LOGO! logic modules. Users can apply a password to project files to protect proprietary control logic. The confidentiality of that password depends on the strength and secrecy of the encryption key protecting the project file.
In affected versions, the project encryption relies on a static AES master key compiled into the application. Because the key is identical across every installation, it is not a secret. Any user with access to the software distribution can retrieve the key material once and reuse it against project files from any other installation.
Root Cause
The root cause is Use of Hard-coded Cryptographic Key [CWE-321]. The AES master key is embedded in the LOGO! Soft Comfort application code and remains constant across releases and installations. Password protection on project files is therefore reduced to a symmetric operation using a known key rather than a secret derived from user input.
Attack Vector
Exploitation requires local access to a system that has LOGO! Soft Comfort installed, or access to the application binaries and a target project file. An attacker extracts the hardcoded key from the application files or from process memory using standard reverse engineering or memory inspection tools. The attacker then uses the recovered key to decrypt the target project file or to strip the stored password without ever supplying the user-defined value.
The outcome is disclosure of protected LOGO! project logic and the ability to modify or reuse projects that were intended to remain confidential. See the Siemens Security Advisory SSA-751328 for vendor technical details.
Detection Methods for CVE-2026-57262
Indicators of Compromise
- Unexpected access to LOGO! Soft Comfort installation directories or project file (.lsc) locations by users or processes that do not normally handle engineering workstation content.
- Presence of debugging, disassembly, or memory-inspection tools (for example x64dbg, Ghidra, procdump) on engineering workstations running LOGO! Soft Comfort.
- Copies of LOGO! project files appearing on removable media, personal cloud sync folders, or transferred outbound over the network.
Detection Strategies
- Monitor file-access telemetry on engineering workstations for reads of LOGO! Soft Comfort executables, DLLs, and project files by non-engineering processes.
- Alert on process memory dumps or handle-open events targeting the LOGO! Soft Comfort process.
- Track project file movement outside of approved engineering repositories using data loss prevention or endpoint file-activity logging.
Monitoring Recommendations
- Enable command-line and process-creation logging on operational technology (OT) engineering workstations and forward events to a central analytics platform.
- Baseline the set of users and hosts that legitimately open LOGO! Soft Comfort and alert on deviations.
- Audit removable media use and outbound file transfers from engineering workstations.
How to Mitigate CVE-2026-57262
Immediate Actions Required
- Upgrade LOGO! Soft Comfort to V9 or later on every engineering workstation.
- Restrict LOGO! Soft Comfort installations to authenticated engineering users and remove the software from general-purpose workstations.
- Treat existing project files encrypted under the hardcoded key as compromised for confidentiality purposes and rotate any embedded secrets they contain.
Patch Information
Siemens addresses the hardcoded AES master key in LOGO! Soft Comfort V9 and later. Refer to the Siemens Security Advisory SSA-751328 for the fixed version guidance and any updated remediation steps.
Workarounds
- Store LOGO! project files only on access-controlled file shares with auditing enabled, and restrict access to authorized engineers.
- Isolate engineering workstations on a segmented OT network and block direct internet access to reduce local access opportunities.
- Apply full-disk encryption and endpoint controls on engineering workstations so that project files cannot be recovered from lost or stolen devices.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
