DNS-320: Improper Access Control
CVE-2026-16331 is a high-severity improper access control vulnerability in DNS-320 from D-Link, with a CVSS 3.1 base score of 7.3 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected DNS-320 versions: 1.0.2. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.57% chance of exploitation within 30 days, higher than 76% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of DNS-320 you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
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
- LowSome restricted data can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L. Scored by CNA (vuldb.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 5.5 | Medium | CNA (vuldb.com) |
| CVSS 3.1 | 7.3 | High | CNA (vuldb.com) |
| CVSS 2.0 | 7.5 | High | CNA (vuldb.com) |
Official description
A security vulnerability has been detected in D-Link DNS-320 1.0.2. This affects an unknown function of the file /web/function/save_ajax.php. Such manipulation of the argument Malicious Handler leads to unrestricted upload. The attack can be executed remotely. The exploit has been disclosed publicly and may be used.
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: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in DNS-320
- 7.3 High severity
- 7.3 High severity
- 7.3 High severity
- 7.3 High severity
- 7.3 High severity
- 7.2 High severity
Recent Improper Access Control vulnerabilities
- 7.8 High severity
- 7.1 High severity
- 9.6 Critical severity
- 9.1 Critical severity
- 8.1 High severity
- 7.5 High severity
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