DNS-120: Incorrect Privilege Assignment
CVE-2026-4194 is a critical-severity incorrect privilege assignment vulnerability in DNS-120 from D-Link, 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. Affected DNS-120 versions: 20260205. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 5.59% chance of exploitation within 30 days, which is in the top 6.98% of all scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of DNS-120 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
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| D-Link | DNS-120 | 20260205 | Not stated |
| D-Link | DNR-202L | 20260205 | Not stated |
| D-Link | DNS-315L | 20260205 | Not stated |
| D-Link | DNS-320 | 20260205 | Not stated |
| D-Link | DNS-320L | 20260205 | Not stated |
| D-Link | DNS-320LW | 20260205 | Not stated |
| D-Link | DNS-321 | 20260205 | Not stated |
| D-Link | DNR-322L | 20260205 | Not stated |
| D-Link | DNS-323 | 20260205 | Not stated |
| D-Link | DNS-325 | 20260205 | Not stated |
| D-Link | DNS-326 | 20260205 | Not stated |
| D-Link | DNS-327L | 20260205 | Not stated |
| D-Link | DNR-326 | 20260205 | Not stated |
| D-Link | DNS-340L | 20260205 | Not stated |
| D-Link | DNS-343 | 20260205 | Not stated |
| D-Link | DNS-345 | 20260205 | Not stated |
| D-Link | DNS-726-4 | 20260205 | Not stated |
| D-Link | DNS-1100-4 | 20260205 | Not stated |
| D-Link | DNS-1200-05 | 20260205 | Not stated |
| D-Link | DNS-1550-04 | 20260205 | Not stated |
| D-Link | Dnr-202l Firmware | 2026-02-05 and earlier | Not stated |
| D-Link | Dnr-326 Firmware | 2026-02-05 and earlier | Not stated |
| D-Link | Dns-1100-4 Firmware | 2026-02-05 and earlier | Not stated |
| D-Link | Dns-120 Firmware | 2026-02-05 and earlier | Not stated |
| D-Link | Dns-1200-05 Firmware | 2026-02-05 and earlier | Not stated |
Version data comes from the organisation that assigned the CVE; 15 further products are omitted here. 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 NVD.
| 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 3.1 | 9.8 | Critical | NVD |
| CVSS 2.0 | 7.5 | High | CNA (vuldb.com) |
Official description
A vulnerability was detected in D-Link DNS-120, DNR-202L, DNS-315L, DNS-320, DNS-320L, DNS-320LW, DNS-321, DNR-322L, DNS-323, DNS-325, DNS-326, DNS-327L, DNR-326, DNS-340L, DNS-343, DNS-345, DNS-726-4, DNS-1100-4, DNS-1200-05 and DNS-1550-04 up to 20260205. The impacted element is the function cgi_set_wto of the file /cgi-bin/system_mgr.cgi. Performing a manipulation results in improper access controls. Remote exploitation of the attack is possible. The exploit is now public and may be used.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Privilege Assignment
A product incorrectly assigns a privilege to a particular actor, creating an unintended sphere of control for that 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.
- Run your code using the lowest privileges that are required to accomplish the necessary tasks. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.
More Incorrect Privilege Assignment vulnerabilities (CWE-266)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- vuldb.com/?id.351106Third Party Advisory, VDB Entry
- vuldb.com/?submit.769853Third Party Advisory, VDB Entry
Technical write-ups (may include proof of concept)
- github.com/wudipjq/my_vuln/blob/main/D-Link8/vuln_96/96.mdExploit, Third Party Advisory
Other references
- vuldb.com/?ctiid.351106Permissions Required, VDB Entry
- dlink.com/Product
Other vulnerabilities in DNS-120
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
Recent Incorrect Privilege Assignment vulnerabilities
- 7.5 High severity
- 9.8 Critical severity
- 7.8 High severity
- 7.3 High severity
- 9.8 Critical severity
- 7.3 High severity
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