Single-A: External Control of File Name or Path
CVE-2026-35079 is a high-severity external control of file name or path vulnerability in Single-A from MBS, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, 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 0.37% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
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.
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
- LowA basic user account is enough.
- 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:L/UI:N/S:U/C:N/I:H/A:H. Scored by CNA (cert.vde.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 7.2 | High | CNA (cert.vde.com) |
| CVSS 3.1 | 8.1 | High | CNA (cert.vde.com) |
Official description
The ugw-restore method allows a remote attacker with user privileges to delete arbitrary local files due to insufficient validation of user-controlled input.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: External Control of File Name or Path
The product allows user input to control or influence paths or file names that are used in filesystem operations.
How developers prevent this class of flaw
- When the set of filenames is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames, and reject all other inputs. For example, ID 1 could map to inbox.txt and ID 2 could map to profile.txt. Features such as the ESAPI AccessReferenceMap provide this capability.
- Run your code in a jail or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict all access to files within a particular directory. Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
More External Control of File Name or Path vulnerabilities (CWE-73)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, 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 External Control of File Name or Path vulnerabilities
- 7.3 High severity
- 8.2 High severity
- 7.5 High severity
- 8.8 High severity
- 8.1 High severity
- 7.5 High severity
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