0765-110x/0100-0000: Hidden Functionality
CVE-2026-4769 is a critical-severity hidden functionality vulnerability in 0765-110x/0100-0000 from WAGO, 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 1.2.1.100 as the first without the flaw, so updating 0765-110x/0100-0000 to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.76% chance of exploitation within 30 days, higher than 56% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update 0765-110x/0100-0000 to 1.2.1.100 or a later version.
- Update 0765-120x/0100-0000 to 1.2.7.100 or a later version.
- Update 0765-150x/0100-0000 to 1.2.7.103 or a later version.
- 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 |
|---|---|---|---|
| WAGO | 0765-110x/0100-0000 | 1.0.0.0 up to, but not including, 1.2.1.100 | 1.2.1.100 |
| WAGO | 0765-120x/0100-0000 | 1.0.0.0 up to, but not including, 1.2.7.100 | 1.2.7.100 |
| WAGO | 0765-150x/0100-0000 | 1.0.0.0 up to, but not including, 1.2.7.103 | 1.2.7.103 |
| WAGO | 0765-2101/0100-0000 | 1.0.0.0 up to, but not including, 1.2.1.102 | 1.2.1.102 |
| WAGO | 0765-2102/0100-0000 | 1.0.0.0 up to, but not including, 1.2.5.101 | 1.2.5.101 |
| WAGO | 0765-410x/0100-0000 | 1.0.0.0 up to, but not including, 1.2.1.100 | 1.2.1.100 |
| WAGO | 0765-420x/0100-0000 | 1.0.0.0 up to, but not including, 1.2.7.100 | 1.2.7.100 |
| WAGO | 0765-450x/0100-0000 | 1.0.0.0 up to, but not including, 1.2.7.103 | 1.2.7.103 |
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
Certain devices in the WAGO System I/O Field series activate an internal diagnostic capability during the initial startup sequence. This functionality is not formally documented and becomes accessible without authentication for a brief period in the early boot phase. During this window, an unauthenticated remote attacker can gain access to the internal system processes, resulting in full system compromise.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Hidden Functionality
The product contains functionality that is not documented, not part of the specification, and not accessible through an interface or command sequence that is obvious to the product's users or administrators.
How developers prevent this class of flaw
- Always verify the integrity of the product that is being installed.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
References
Other references
Recent Hidden Functionality vulnerabilities
- 9.8 Critical severity
- 9.8 Critical severity
- 8.8 High severity
- 10.0 Critical severity
- 7.2 High severity
- 9.5 Critical severity
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