Authenticated code execution via unchecked CGI parameter copy
Published Mar 16, 2026 · Updated Mar 16, 2026
Stack-based buffer overflow in gui_mgr.cgi on affected D-Link DNS and DNR appliances allows remote authenticated users to execute code. The cgi_myfavorite_del_user and cgi_myfavorite_verify handlers copy oversized f_user_lst or f_lst values into stack buffers without bounds checks, overwriting return addresses. Authenticated web-management access is required; the published proofs demonstrate a persistent service crash, while code execution is asserted but not demonstrated.
Summary
What happened
Stack-based buffer overflow in gui_mgr.cgi on affected D-Link DNS and DNR appliances allows remote authenticated users to execute code. The cgi_myfavorite_del_user and cgi_myfavorite_verify handlers copy oversized f_user_lst or f_lst values into stack buffers without bounds checks, overwriting return addresses. Authenticated web-management access is required; the published proofs demonstrate a persistent service crash, while code execution is asserted but not demonstrated.
The record
- CVE
- CVE-2026-4213
- 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?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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
- cgi_myfavorite_verify f_lst proof of conceptproof of concept · demonstrated
- cgi_myfavorite_del_user f_user_lst 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