VulnerabilityPublished 15 Mar 2026

CVE-2026-4194: D-Link DNS-120 · Improper Access Controls

Affects D-Link DNS-120Source CVE Database V5

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Public exploit available · CVSS 6.9 Medium.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 4.0 base score

6.9Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 4.9% chance of exploitation in 30 days – higher than 92% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

Base metrics

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: Low
Vulnerable system integrity: Low
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Threat metrics

Exploit Maturity: POC

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Vulnerable System.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
Exploit Maturity: POC: Based on threat intelligence sources each of the following must apply: · Proof-of-concept is publicly available · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 15 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
CVSS exploit maturity: proof of concept public
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CVSS vector, the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
D-LinkDNS-120	Affected =20260205	Fixed in–
D-LinkDNR-202L	Affected =20260205	Fixed in–
D-LinkDNS-315L	Affected =20260205	Fixed in–
D-LinkDNS-320	Affected =20260205	Fixed in–
D-LinkDNS-320L	Affected =20260205	Fixed in–
D-LinkDNS-320LW	Affected =20260205	Fixed in–

AI-suggested

Immediately isolate affected D-Link NAS devices from untrusted networks to prevent remote exploitation.
Restrict access to the management interface by implementing network segmentation and firewall rules allowing only trusted IP addresses.
Disable remote management features if not required.
Monitor network traffic for unusual access patterns targeting /cgi-bin/system_mgr.cgi or related CGI endpoints.
Regularly back up NAS data to secure offline storage to mitigate potential data loss.
Contact D-Link support for any available patches or firmware updates addressing this vulnerability and apply them promptly once released.
If patches are unavailable, consider replacing affected devices with models not impacted by this vulnerability.
Implement strong network access controls and multi-factor authentication on management interfaces where possible to reduce risk.
Educate IT staff about this vulnerability and ensure incident response plans include steps for NAS device compromise.

Description

CVE-2026-4194 is a medium severity vulnerability affecting multiple D-Link NAS devices, including the DNS-120 and various other models. The flaw exists in the cgi_set_wto function within the /cgi-bin/system_mgr.cgi file, leading to improper access controls. This vulnerability allows remote attackers to manipulate the system without authentication or user interaction. The exploit is publicly available, increasing the risk of exploitation. Although no known exploits are currently observed in the wild, the vulnerability could potentially allow unauthorized access or modification of device settings. The CVSS 4.0 score is 6.9, reflecting a moderate risk due to ease of exploitation and impact on confidentiality, integrity, and availability. Organizations using affected D-Link NAS devices should prioritize mitigation to prevent unauthorized remote access.

Impact

The vulnerability could allow remote attackers to bypass authentication and gain unauthorized access to the management interface of affected D-Link NAS devices. This can lead to unauthorized disclosure of sensitive information stored on the device, unauthorized modification of device settings, or disruption of NAS services. For organizations, this could result in data breaches, loss of data integrity, and potential downtime impacting business operations. Since NAS devices often store critical backups and shared files, compromise could facilitate lateral movement within networks or serve as a foothold for further attacks. The public availability of exploit code increases the risk of widespread exploitation, especially targeting unpatched or poorly secured devices. The lack of authentication requirement and ease of exploitation make this a significant threat to organizations using these devices in enterprise, SMB, or home environments.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 23 Mar 2026, 00:43 UTC

Technical details

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