Which versions of Dir 816 are affected by CVE-2026-4181?

A critical remote code execution vulnerability (CVE-2026-4181, CVSS 9.8) affects D-Link DIR-816 routers running firmware 1.10CNB05 with no patch available.

Is there a public PoC exploit available for CVE-2026-4181?

Yes, a public proof-of-concept exploit is available for CVE-2026-4181. Prioritise patching immediately. EPSS: 0.1%.

How to fix or mitigate CVE-2026-4181?

Within 24 hours: Audit network inventory to identify all DIR-816 1.10CNB05 devices and isolate them from production networks. Within 7 days: Develop decommissioning plan for affected devices and procure replacement hardware from supported vendors. Within 30 days: Complete replacement of all vulnerable devices and validate network segmentation controls are in place.

Dir 816 CVE-2026-4181

Q: What is the CVSS score of CVE-2026-4181?

CVE-2026-4181 has a CVSS 4.0 base score of 8.9 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.1%.

EUVD-2026-12233 HIGH

Stack-based Buffer Overflow (CWE-121)

2026-03-15 VulDB

Buffer Overflow D-Link Stack Overflow Dir 816 D-Link

8.9

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

8.9 HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

PoC Detected

Apr 06, 2026 - 14:12 vuln.today

Public exploit code

EUVD ID Assigned

Mar 15, 2026 - 17:00 euvd

EUVD-2026-12233

Analysis Generated

Mar 15, 2026 - 17:00 vuln.today

CVE Published

Mar 15, 2026 - 16:02 nvd

HIGH 8.9

DescriptionCVE.org

A security flaw has been discovered in D-Link DIR-816 1.10CNB05. This affects an unknown function of the file /goform/form2RepeaterStep2.cgi of the component goahead. The manipulation of the argument key1/key2/key3/key4/pskValue results in stack-based buffer overflow. The attack may be launched remotely. The exploit has been released to the public and may be used for attacks. This vulnerability only affects products that are no longer supported by the maintainer.

AnalysisAI

Critical stack-based buffer overflow vulnerability in the D-Link DIR-816 router (firmware version 1.10CNB05) that allows remote attackers to execute arbitrary code without authentication. A public proof-of-concept exploit is available, and the vulnerability affects end-of-life products no longer supported by D-Link, making this a high-risk issue for organizations still using these devices.

Technical ContextAI

The vulnerability exists in the goahead web server component, specifically in the /goform/form2RepeaterStep2.cgi file. According to the CPE identifier (cpe:2.3:a:d-link:dir-816:*:*:*:*:*:*:*:*), all versions of the DIR-816 router are affected. The root cause is CWE-121 (Stack-based Buffer Overflow), where improper validation of input parameters (key1, key2, key3, key4, and pskValue) allows an attacker to overflow the stack buffer, potentially overwriting return addresses and gaining control of execution flow.

RemediationAI

Since D-Link no longer supports the DIR-816 product line, no official patches will be released. Organizations must immediately replace these devices with supported alternatives. As an emergency mitigation, block external access to the device's web interface and restrict management access to trusted IP addresses only. However, given the critical nature and public exploit availability, device replacement is the only reliable remediation. Check D-Link's official website (https://www.dlink.com/) for recommended replacement models.