Authenticated code execution via unchecked f_idx copy
Published Mar 16, 2026 · Updated Mar 16, 2026
Stack-based buffer overflow in D-Link NAS and NVR firmware through 20260205 allows remote authenticated users to execute code via HTTP. Downloads_Schedule_Info in /cgi-bin/download_mgr.cgi copies the attacker-controlled f_idx parameter into a fixed-size stack variable without checking its length, overwriting the function return address. Authenticated access to the web-management interface is required; an oversized request demonstrably crashes the appliance, while return-address control supports arbitrary code execution.
Summary
What happened
Stack-based buffer overflow in D-Link NAS and NVR firmware through 20260205 allows remote authenticated users to execute code via HTTP. Downloads_Schedule_Info in /cgi-bin/download_mgr.cgi copies the attacker-controlled f_idx parameter into a fixed-size stack variable without checking its length, overwriting the function return address. Authenticated access to the web-management interface is required; an oversized request demonstrably crashes the appliance, while return-address control supports arbitrary code execution.
The record
- CVE
- CVE-2026-4212
- Published
- Mar 16, 2026
- Updated
- Mar 16, 2026
- Vendor
- D-Link
- Product
- DNR-322L
- Classifications
- CWE-121, CWE-787, CWE-119, T1190
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 16, 2026CVE publishedPublication date reported by the CVE source.
- Mar 16, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=20260205
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Oversized f_idx HTTP request proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo