CVE-2026-4212
Published: 16 March 2026
Summary
CVE-2026-4212 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Dlink Dnr-202L Firmware. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 18.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-16 (Memory Protection).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly remediates the stack-based buffer overflow vulnerability by applying vendor firmware patches for the affected D-Link NAS devices.
Enforces validation of inputs to the Downloads_Schedule_Info function in /cgi-bin/download_mgr.cgi to prevent crafted data from triggering the buffer overflow.
Provides runtime memory protections such as stack canaries, ASLR, or non-executable memory to mitigate exploitation of the stack-based buffer overflow even if invalid input reaches the vulnerable function.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Stack-based buffer overflow in public-facing /cgi-bin/download_mgr.cgi enables remote authenticated RCE on NAS devices (T1190) and directly supports privilege escalation from low-priv accounts to full system compromise (T1068).
NVD Description
A security vulnerability has been 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. This affects the function Downloads_Schedule_Info of the file…
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/cgi-bin/download_mgr.cgi. Such manipulation leads to stack-based buffer overflow. The attack can be launched remotely. The exploit has been disclosed publicly and may be used.
Deeper analysisAI
CVE-2026-4212 is a stack-based buffer overflow vulnerability (associated with CWE-119, CWE-121, and CWE-787) in the Downloads_Schedule_Info function of the /cgi-bin/download_mgr.cgi script. It affects multiple D-Link NAS devices running firmware up to version 20260205, specifically the models 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. The issue was published on 2026-03-16 and carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
The vulnerability enables remote exploitation by low-privileged users (PR:L) over the network with low complexity and no user interaction required. Attackers can trigger the buffer overflow via crafted manipulation of the affected function, potentially achieving high-impact compromise of confidentiality, integrity, and availability, such as arbitrary code execution or system crashes on vulnerable devices.
Advisories on VulDB (ctiid.351123, id.351123, submit.770442) document the vulnerability details, while a GitHub repository (https://github.com/wudipjq/my_vuln/blob/main/D-Link8/vuln_161/161.md) publicly discloses an exploit that may be used in attacks. Practitioners should monitor the D-Link website (https://www.dlink.com/) for firmware updates or mitigation guidance.
The exploit has been publicly disclosed, increasing the risk of active exploitation against unpatched D-Link NAS devices.
Details
- CWE(s)