UBR-01 Mk II: Missing Authorization
CVE-2025-41764 is a critical-severity missing authorization vulnerability in UBR-01 Mk II from MBS, with a CVSS 3.1 base score of 9.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 6.0.1.0 as the first without the flaw, so updating UBR-01 Mk II to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.45% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update UBR-01 Mk II to 6.0.1.0 or a later version.
- Update UBR-02 to 6.0.1.0 or a later version.
- Update UBR-LON to 6.0.1.0 or a later version.
- Read the advisory on mbs-solutions.de for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| MBS | UBR-01 Mk II | before 6.0.1.0 | 6.0.1.0 |
| MBS | UBR-02 | before 6.0.1.0 | 6.0.1.0 |
| MBS | UBR-LON | before 6.0.1.0 | 6.0.1.0 |
| Mbs-solutions | Universal Bacnet Router Firmware | before 6.0.1.0 | 6.0.1.0 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H. Scored by CNA (cert.vde.com).
Official description
Due to insufficient authorization enforcement, an unauthorized remote attacker can exploit the wwwupdate.cgi endpoint to upload and apply arbitrary updates.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Missing Authorization
The product does not perform an authorization check when an actor attempts to access a resource or perform an action.
How developers prevent this class of flaw
- Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework and the OWASP ESAPI Access Control feature.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in UBR-01 Mk II
- 7.5 High severity
- 7.2 High severity
- 8.8 High severity
- 9.1 Critical severity
- 7.8 High severity
- 8.8 High severity
Recent Missing Authorization vulnerabilities
- 8.8 High severity
- 8.8 High severity
- 8.2 High severity
- 9.8 Critical severity
- 7.1 High severity
- 7.5 High severity
Spotted an error? Tell us.