CVE-2026-57263: LOGO! Soft Comfort Hash Vulnerability

CVE-2026-57263 Overview

CVE-2026-57263 affects Siemens LOGO! Soft Comfort in all versions prior to V9. The project password feature stores user-supplied passwords as unsalted SHA-256 hashes inside the project file. An attacker who obtains a project file can perform offline dictionary or brute-force attacks against the hash without any rate limiting. The absence of a salt allows precomputed rainbow tables and GPU-accelerated cracking rigs to recover weak or reused passwords quickly. The flaw maps to [CWE-759: Use of a One-Way Hash without a Salt] and undermines the confidentiality guarantees the project password feature is intended to provide for industrial engineering artifacts.

Critical Impact
Attackers who exfiltrate a LOGO! Soft Comfort project file can recover the project password offline and gain access to protected industrial control logic and configuration data.

Affected Products

Siemens LOGO! Soft Comfort (all versions prior to V9)

Discovery Timeline

2026-08-11 - CVE-2026-57263 published to the National Vulnerability Database (NVD)
2026-08-11 - Last updated in NVD database

Technical Details for CVE-2026-57263

Vulnerability Analysis

LOGO! Soft Comfort is Siemens' engineering software for programming LOGO! logic modules used in small-scale industrial and building automation. Engineers can set a project password to restrict who can open or modify a project file. The password is hashed with SHA-256 and stored inside the project file, but no per-project salt is applied before hashing.

Because SHA-256 is a fast, general-purpose cryptographic hash rather than a password-hashing function, and because no salt is used, the stored digest offers minimal resistance to offline attack. An attacker who acquires a project file can extract the hash and test billions of candidate passwords per second on commodity GPUs. Identical passwords across multiple project files produce identical hashes, allowing bulk cracking and rainbow-table reuse.

Root Cause

The root cause is a design defect in the password storage scheme: the project password is passed directly into SHA-256 without a salt and without a key-derivation function such as PBKDF2, bcrypt, scrypt, or Argon2. This pattern is captured by [CWE-759: Use of a One-Way Hash without a Salt].

Attack Vector

Exploitation requires local access to a project file. Files may be obtained from engineering workstations, backup shares, source repositories, email attachments, or removable media. Once the file is retrieved, cracking is performed offline on attacker-controlled hardware and produces the cleartext project password. The attacker can then open the project in LOGO! Soft Comfort, read the control logic, alter automation behavior, or reuse the password against other systems.

No verified public exploit code is available for CVE-2026-57263. Refer to the Siemens Security Advisory SSA-751328 for vendor-provided technical details.

Detection Methods for CVE-2026-57263

Indicators of Compromise

Unexpected access to or copying of LOGO! Soft Comfort project files (typically .lsc files) from engineering workstations, file shares, or backup locations.
Presence of password-cracking tools such as hashcat or john on engineering or IT systems.
Modifications to LOGO! project logic that do not correspond to an approved change record.

Detection Strategies

Monitor endpoint file access telemetry for reads of LOGO! project files by processes other than LOGOComfort.exe or approved backup agents.
Alert on outbound transfers of engineering artifacts to external destinations, webmail, or cloud storage.
Correlate authentication events on LOGO! devices with recent access to the corresponding project files.

Monitoring Recommendations

Enable file-access auditing on directories that store LOGO! Soft Comfort projects and forward events to a centralized SIEM.
Track version-control commits and file-share activity for engineering repositories that hold LOGO! projects.
Review privileged access to engineering workstations and identify accounts with unnecessary read permission on project files.

How to Mitigate CVE-2026-57263

Immediate Actions Required

Upgrade LOGO! Soft Comfort to V9 or later, in line with the guidance published in Siemens Security Advisory SSA-751328.
Treat existing project files created with vulnerable versions as compromised if they have left controlled storage, and rotate any reused passwords.
Restrict access to LOGO! Soft Comfort project files to authorized engineers only and store them on access-controlled shares.

Patch Information

Siemens addresses this issue in LOGO! Soft Comfort V9 and later. Consult Siemens Security Advisory SSA-751328 for the authoritative fix version, download location, and any additional hardening steps.

Workarounds

Use long, high-entropy, unique passwords for each LOGO! project to raise the cost of offline cracking.
Store project files on encrypted volumes and transmit them only over encrypted channels.
Segment engineering workstations from general-purpose IT networks to limit exposure of project files to attackers.