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-32...
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
AI Analyst Comment
Remediation
Apply vendor security updates immediately. Monitor for exploitation attempts and review access logs.
---METADATA---
VENDOR: D-Link
PRODUCT: DNS and DNR series NAS devices
AFFECTED_VERSIONS: All versions up to and including 20260205
CONFIDENCE: high
MISSING: patch
CREDITS: pjqwudi (VulDB User) (reporter)
SOURCES_JSON: [{"url":"https://vuldb.com/?id.351124","name":"VDB-351124 | D-Link DNS-1550-04 gui_mgr.cgi cgi_myfavorite_verify stack-based overflow","tags":["vdb-entry","technical-description"]},{"url":"https://vuldb.com/?ctiid.351124","name":"VDB-351124 | CTI Indicators (IOB, IOC, IOA)","tags":["signature","permissions-required"]},{"url":"https://vuldb.com/?submit.770443","name":"Submit #770443 | D-Link DNS-120/202L/315L/320/320L/320LW/321/322L/323/325/326/327L/326/340L/343/345/726-4/1100-4/1200-05","tags":["third-party-advisory"]},{"url":"https://vuldb.com/?submit.770444","name":"Submit #770444 | D-Link DNS-120/202L/315L/320/320L/320LW/321/322L/323/325/326/327L/326/340L/343/345/726-4/1100-4/1200-05","tags":["third-party-advisory"]},{"url":"https://github.com/wudipjq/my_vuln/blob/main/D-Link8/vuln_162/162.md","name":null,"tags":["related"]},{"url":"https://github.com/wudipjq/my_vuln/blob/main/D-Link8/vuln_163/163.md","name":null,"tags":["exploit"]},{"url":"https://www.dlink.com/","name":null,"tags":["product"]}]
PROFILE: batch@eb21ac00f78b
MODEL: gemini-3.1-flash-lite
GENERATED: 2026-08-29T14:11:39.286Z
---END_METADATA---
Description Summary:
A stack-based buffer overflow exists in multiple D-Link NAS devices due to improper input validation in the cgi_myfavorite_verify function, allowing remote attackers to trigger a crash or code execution.
Executive Summary:
A critical stack-based buffer overflow vulnerability in various D-Link network storage devices allows remote attackers to compromise system integrity and availability.
Vulnerability Details
CVE-ID: CVE-2026-4213
Affected Software: D-Link DNS and DNR series NAS devices (including DNS-120, DNR-202L, DNS-315L, DNS-320, DNS-320L, DNS-320LW, and others).
Affected Versions: All firmware versions up to 20260205.
Vulnerability: The vulnerability is located within the /cgi-bin/gui_mgr.cgi endpoint, specifically in the cgi_myfavorite_verify function. An authenticated attacker can send a maliciously crafted HTTP POST request containing an overly long f_lst parameter, which triggers a stack-based buffer overflow and permits arbitrary code execution.
Business Impact
Successful exploitation of this vulnerability allows an attacker to execute arbitrary code or cause a persistent denial of service on affected storage devices. Given the CVSS score of 8.8, this represents a high risk to business operations, as these devices often house sensitive data backups. Compromise of these units could lead to unauthorized access to stored corporate information or total loss of data availability.
Remediation Plan
Immediate Action: Monitor official D-Link support channels for firmware updates that address this buffer overflow. If no patch is currently available, restrict access to the management interface of the affected devices to trusted internal IP addresses only.
Proactive Monitoring: Review web server access logs for anomalous POST requests directed at /cgi-bin/gui_mgr.cgi, particularly those containing unusually long strings within the f_lst parameter.
Compensating Controls: Deploy a Web Application Firewall (WAF) rule to inspect and block HTTP requests to the /cgi-bin/gui_mgr.cgi endpoint that contain excessive data lengths in the f_lst field.
Exploitation Status
Public Exploit Available: Yes, a published proof-of-concept exists and is documented in the technical write-up referenced in the CVE record.
Analyst Notes: As of March 18, 2026, there is no confirmed active exploitation in the wild; however, per CISA's SSVC assessment a proof-of-concept exists, so exploitation risk should be treated as credible. The vulnerability is highly exploitable as it requires no complex bypasses beyond authenticated access to the management interface.
Analyst Recommendation
Due to the availability of proof-of-concept code and the critical impact of remote code execution, this vulnerability poses a significant risk to the integrity of backup infrastructure. Administrators should prioritize isolating these devices from external networks immediately and apply the vendor-provided firmware update as soon as it becomes available.