Single-A: Use of Default Password
CVE-2026-35075 is a critical-severity use of default password vulnerability in Single-A from MBS, with a CVSS 3.1 base score of 9.8 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 V6_00_07 as the first without the flaw, so updating Single-A to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.47% 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 Single-A to V6_00_07 or a later version.
- Update Double-A Profibus to V6_00_07 or a later version.
- Update Double-A x-link to V6_00_07 or a later version.
- Read the advisory on certvde.com 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 | Single-A | V1_00_00 up to, but not including, V6_00_07 | V6_00_07 |
| MBS | Double-A Profibus | V1_00_00 up to, but not including, V6_00_07 | V6_00_07 |
| MBS | Double-A x-link | V1_00_00 up to, but not including, V6_00_07 | V6_00_07 |
| MBS | Single-X | V1_00_00 up to, but not including, V6_00_07 | V6_00_07 |
| MBS | Double-X CAN | V1_00_00 up to, but not including, V6_00_07 | V6_00_07 |
| MBS | Double-X DALI | V1_00_00 up to, but not including, V6_00_07 | V6_00_07 |
| MBS | Double-X KNX | V1_00_00 up to, but not including, V6_00_07 | V6_00_07 |
| MBS | Double-X LON | V1_00_00 up to, but not including, V6_00_07 | V6_00_07 |
| MBS | Double-X M-Bus | V1_00_00 up to, but not including, V6_00_07 | V6_00_07 |
| MBS | Double-X PROFINET | V1_00_00 up to, but not including, V6_00_07 | V6_00_07 |
| MBS | Double-X x-link | V1_00_00 up to, but not including, V6_00_07 | V6_00_07 |
| MBS | Triple-X KNX+DALI | V1_00_00 up to, but not including, V6_00_07 | V6_00_07 |
| MBS | Triple-X KNX+LON | V1_00_00 up to, but not including, V6_00_07 | V6_00_07 |
| MBS | Triple-X KNX+M-Bus | V1_00_00 up to, but not including, V6_00_07 | V6_00_07 |
| MBS | Triple-X PROFINET+DALI | V1_00_00 up to, but not including, V6_00_07 | V6_00_07 |
| MBS | Triple-X PROFINET+KNX | V1_00_00 up to, but not including, V6_00_07 | V6_00_07 |
| MBS | Triple-X PROFINET+LON | V1_00_00 up to, but not including, V6_00_07 | V6_00_07 |
| MBS | Triple-X PROFINET+M-Bus | V1_00_00 up to, but not including, V6_00_07 | V6_00_07 |
| Mbs-solutions | Universal Gateway Firmware | before 6_00_07 | 6_00_07 |
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
- HighAll data handled by the component can be read.
- 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:H/I:H/A:H. Scored by CNA (cert.vde.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 9.3 | Critical | CNA (cert.vde.com) |
| CVSS 3.1 | 9.8 | Critical | CNA (cert.vde.com) |
Official description
An unauthenticated remote attacker can recover a default, hard coded password from a firmware image and thus gain full access to all affected devices.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of Default Password
The product uses default passwords for potentially critical functionality.
How developers prevent this class of flaw
- Prohibit use of default, hard-coded, or other values that do not vary for each installation of the product - especially for separate organizations.
- Ensure that product documentation clearly emphasizes the presence of default passwords and provides steps for the administrator to change them.
- Force the administrator to change the credential upon installation.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in Single-A
- 8.8 High severity
- 8.1 High severity
- 8.1 High severity
- 8.1 High severity
- 8.1 High severity
- 8.1 High severity
Recent Use of Default Password vulnerabilities
- 9.8 Critical severity
- 9.8 Critical severity
- 7.3 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
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