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Universal Bacnet Router FirmwareOperating system · Mbs Solutions

CVE-2025-41755

MEDIUM · 6.5 CVSS v3.1 Published 2026-03-09
Fix available
A fix is available. Upgrade to 6.0.1.0 or later.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A low-privileged remote attacker can exploit the ubr-logread method in wwwubr.cgi to read arbitrary files on the system. The endpoint accepts a parameter specifying the log file to open (e.g., /tmp/weblog{some_number}), but this parameter is not properly validated, allowing an attacker to modify it to reference any file and retrieve its contents.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A path traversal vulnerability in the ubr-logread functionality of wwwubr.cgi allows a low-privileged remote attacker to read arbitrary files by manipulating an unsanitized parameter that specifies the log file path. The endpoint accepts a path like /tmp/weblog{some_number} but fails to validate or restrict access, enabling traversal sequences to access system files.

MitigationImplement strict input validation with whitelist-based filtering for allowed log file paths, use canonical path resolution to detect traversal attempts, and restrict file read operations to an allowed directory. If the logread functionality is not essential, disable it entirely.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Universal Bacnet Router FirmwareOperating system
Affected:< 6.0.1.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the Universal Bacnet Router firmware version
    Access the device's web interface or administrative console and locate the firmware version information, typically found in System Info, Status, or About pages. Alternatively, check via CLI if available (e.g., 'show version' or 'sysinfo').
    Affected if The firmware version is lower than 6.0.1.0
  2. Confirm wwwubr.cgi endpoint is accessible
    Attempt to access the wwwubr.cgi endpoint on the device's web server. This is typically found at http://<device_ip>/wwwubr.cgi or similar path depending on the device's web root configuration.
    Affected if The endpoint returns a valid response (200 OK) rather than a 404 or access denied error, indicating the web interface is active.
  3. Verify the ubr-logread functionality is enabled
    Inspect the web server configuration or device settings to confirm whether the logread functionality (the ubr-logread parameter or log viewing feature) is not disabled. Check for any configuration flags like 'enable_logread' or similar in the device's configuration files or web interface settings.
    Affected if The logread functionality is enabled and accessible without administrative restrictions.
  4. Test for path traversal vulnerability (authorized internal check only)
    If you have authorized access, attempt a controlled test by providing a path traversal sequence (e.g., ../../../etc/passwd) to the log file parameter in wwwubr.cgi and observe if arbitrary files can be read. This should only be done in a non-production, authorized testing environment.
    Affected if The device returns content from files outside the /tmp/weblog* directory, confirming the path traversal vulnerability is present.

You are affected if the device runs Universal Bacnet Router firmware version below 6.0.1.0, has the wwwubr.cgi endpoint exposed, and has the ubr-logread functionality enabled - the path traversal vulnerability allows reading files outside the intended /tmp/weblog directory.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 6.0.1.0 or later
Fixed in 6.0.1.0
Interim mitigation

Implement strict input validation with whitelist-based filtering for allowed log file paths, use canonical path resolution to detect traversal attempts, and restrict file read operations to an allowed directory. If the logread functionality is not essential, disable it entirely.

Recommended fix Moderate confidence

6.0.1.0

  1. Download the Universal Bacnet Router Firmware version 6.0.1.0 or later from the vendor's official source (www.mbs-solutions.de)
  2. Access the router's administrative web interface or management console
  3. Navigate to the firmware upgrade or system maintenance section
  4. Upload the firmware file (6.0.1.0 or later) to the device
  5. Confirm the upgrade and wait for the device to reboot
  6. Verify the new firmware version is installed successfully
  7. Test that the ubr-logread functionality now properly validates the log file parameter

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Universal Bacnet Router Firmware Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
36.0 hours of engineering $6,400
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-41755 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data