VulnerabilityPublished 4 Jun 2025

CVE-2025-5620: D-Link DIR-816 · OS Command Injection

Affects D-Link DIR-816Source CVE Database V5

Not known to be exploited · CVSS 6.9 Medium · end of life, no fix coming : replace or isolate D-Link DIR-816; no fix will be released.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 4.0 base score

6.9Medium

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

EPSS: 7.6% chance of exploitation in 30 days – higher than 94% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: None coming – the product is end of life

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

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

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.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 4 Jun 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
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), the Metasploit, Exploit-DB and nuclei-templates index as of 26 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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

No fix will be released: D-Link DIR-816 is end of life. Replace it, or isolate it from untrusted networks until you can.

AI-suggested

Since no official patches are available due to the product being out of support, European organizations should prioritize the following mitigations: 1) Immediate identification and inventory of all D-Link DIR-816 routers running version 1.10CNB05 within their networks. 2) Replacement of affected devices with supported and updated hardware models to eliminate the vulnerability. 3) If replacement is not immediately feasible, isolate the vulnerable routers from critical network segments and restrict remote management interfaces to trusted IP addresses only. 4) Disable remote administration features on the affected devices to reduce exposure. 5) Implement network-level intrusion detection and prevention systems to monitor for suspicious activities targeting the /goform/setipsec_config endpoint or unusual command execution patterns. 6) Employ network segmentation to limit the impact of a compromised router. 7) Educate IT staff about the risks associated with unsupported hardware and the importance of timely hardware lifecycle management. 8) Regularly monitor threat intelligence feeds for any emerging exploits related to this vulnerability to respond promptly.

Description

A vulnerability, which was classified as critical, was found in D-Link DIR-816 1.10CNB05. Affected is the function setipsec_config of the file /goform/setipsec_config. The manipulation of the argument localIP/remoteIP leads to os command injection. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. This vulnerability only affects products that are no longer supported by the maintainer.

Impact

For European organizations, the impact of CVE-2025-5620 depends largely on the presence and deployment of the affected D-Link DIR-816 routers. If these devices are used within corporate or critical infrastructure networks, the vulnerability could allow attackers to gain unauthorized control over network gateways, leading to data breaches, interception of network traffic, or disruption of network services. The ability to execute OS commands remotely without authentication means attackers could install malware, create persistent backdoors, or disrupt network operations. Given that the product is no longer supported, organizations relying on these devices face increased risk due to the absence of vendor patches. This could be particularly problematic for small and medium enterprises or home office environments where such routers might still be in use. The public availability of exploit code further raises the risk of opportunistic attacks targeting vulnerable devices in Europe, potentially affecting confidentiality and availability of organizational networks.

Summary

CVE-2025-5620 is a security vulnerability identified in the D-Link DIR-816 router, specifically version 1.10CNB05. The flaw exists in the setipsec_config function within the /goform/setipsec_config endpoint. This vulnerability arises from improper sanitization of the localIP and remoteIP parameters, which allows an attacker to inject arbitrary OS commands. Because the vulnerable function processes these parameters without adequate validation, an attacker can remotely execute commands on the underlying operating system with the privileges of the affected service. The vulnerability is remotely exploitable without requiring authentication or user interaction, increasing its risk profile. Although the CVSS v4.0 score is 6.9, categorized as medium severity, the potential for remote command execution typically elevates concern. However, it is important to note that this vulnerability affects only the D-Link DIR-816 model running firmware version 1.10CNB05, which is no longer supported by the vendor. No official patches or updates have been released to address this issue, and no known exploits have been observed in the wild at the time of publication. The public disclosure of the exploit code increases the likelihood of exploitation attempts, especially against unpatched devices still in operation. The vulnerability impacts the confidentiality, integrity, and availability of affected devices, as attackers could execute arbitrary commands, potentially leading to device compromise, network pivoting, or denial of service.

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What to do

Description

AI analysisMachine-generated, updated 7 Jul 2025, 03:10 UTC

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