Cisco IoT Field Network Director (IoT-FND): Improper Access Control
CVE-2026-20167 is a high-severity improper access control vulnerability in Cisco IoT Field Network Director (IoT-FND) from Cisco, with a CVSS 3.1 base score of 7.7 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. Affected Cisco IoT Field Network Director (IoT-FND) versions: 4.5.1; 4.4.3; 4.1.0, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.27% 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 IoT Field Network Director to 5.0.0-117 or a later version.
- Read the advisory on sec.cloudapps.cisco.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Cisco | Cisco IoT Field Network Director (IoT-FND) | 4.5.1; 4.4.3; 4.1.0; 4.1.3; 4.6.1; 4.1.1; 4.4.0; 4.2.0; and 22 more ranges | Not stated |
| Cisco | IoT Field Network Director | before 5.0.0-117 | 5.0.0-117 |
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
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H. Scored by CNA (cisco.com).
Official description
A vulnerability in the web-based management interface of Cisco IoT Field Network Director could allow an authenticated, remote attacker with low privileges to cause a DoS condition on a remotely managed router. This vulnerability is due to improper error handling. An attacker could exploit this vulnerability by submitting crafted input to the web-based management interface. A successful exploit could allow the attacker to request unauthorized files from a remote router, causing the router to reload and resulting in a DoS condition.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Access Control
The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.
How developers prevent this class of flaw
- Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.
- Compartmentalize the system to have safe areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Recent Improper Access Control vulnerabilities
- 9.8 Critical severity
- 7.3 High severity
- 7.3 High severity
- 7.8 High severity
- 9.8 Critical severity
- 8.1 High severity
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