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1. EXECUTIVE SUMMARY

• CVSS v4 9.3
• ATTENTION: Exploitable remotely/low attack complexity
• Vendor: KUNBUS
• Equipment: RevPi Webstatus
• Vulnerability: Incorrect Implementation of Authentication Algorithm

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow attackers to bypass authentication and gain unauthorized access to the application.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

KUNBUS reports the following products are affected:

• Revolution Pi Webstatus: Version 2.4.5 and prior
• Revolution Pi OS Bullseye: 04/2024
• Revolution Pi OS Bullseye: 09/2023
• Revolution Pi OS Bullseye: 07/2023
• Revolution Pi OS Bullseye: 06/2023
• Revolution Pi OS Bullseye: 02/2024

3.2 VULNERABILITY OVERVIEW

3.2.1 INCORRECT IMPLEMENTATION OF AUTHENTICATION ALGORITHM CWE-303

The Revolution Pi Webstatus application is vulnerable to an authentication bypass. The password check is vulnerable to an implicit type conversion. This results in incorrect authentication if the JSON value TRUE is provided in the password parameter hashcode.

CVE-2025-41646 has been assigned to this vulnerability. A CVSS v3.1 base score of 9.8 has been calculated; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

A CVSS v4 score has also been calculated for CVE-2025-41646. A base score of 9.3 has been calculated; the CVSS vector string is (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing, Energy, Transportation Systems, Water and Wastewater Systems
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

Ajay Anto reported this vulnerability to KUNBUS PSIRT, who then reported it to CISA.

4. MITIGATIONS

KUNBUS has identified the following specific workarounds and mitigations users can apply to reduce risk:

• For Revolution Pi Webstatus Version 2.4.5 and prior: Install the updated package Version 2.4.6 either using apt-get update && apt-get upgrade or download it manually and install via dpkg.

For more information, see the associated KUNBUS PSIRT security advisory, Kunbus-2025-0000003 URL generated by system.

CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability, such as:

• Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the Internet.
• Locate control system networks and remote devices behind firewalls and isolating them from business networks.
• When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs). Recognize VPNs may have vulnerabilities, should be updated to the most recent version available, and are only as secure as the connected devices.

CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.

Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.

Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.

No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time.

5. UPDATE HISTORY

• July 10, 2025: Initial Republication of KUNBUS PSIRT Kunbus-2025-0000003