Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/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:XSummary
CVE-2026-4204 is a medium-severity Injection (CWE-74) vulnerability in Dlink Dnr-202L Firmware. Its CVSS base score is 5.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Command and Scripting Interpreter (T1059); ranked in the top 11% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-4204 is a command injection vulnerability affecting multiple D-Link Network Attached Storage (NAS) devices, including 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 running firmware versions up to 20260205. The flaw resides in the /cgi-bin/gui_mgr.cgi script, specifically within functions such as cgi_myfavorite_add, cgi_myfavorite_set, cgi_myfavorite_del, cgi_myfavorite_set_sort_info, cgi_myfavorite_remove_apkg, cgi_myfavorite_compare_apkg, and cgi_mycloud_auto_downlaod. It stems from improper handling of the f_user argument, mapped to CWE-74 (Improper Neutralization of Special Elements) and CWE-77 (Command Injection), with a CVSS v3.1 base score of 6.3 (AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L).
Remote attackers with low-privilege access (PR:L) can exploit this vulnerability over the network without user interaction. By manipulating the f_user argument in the affected CGI endpoints, attackers can inject arbitrary commands, potentially leading to limited impacts on confidentiality, integrity, and availability, such as unauthorized data access, modification of system files, or denial of service on the targeted NAS device.
Advisories and details are available via VulDB entries (ctiid.351116, id.351116, submit.770409) and a GitHub repository documenting the vulnerability and proof-of-concept exploit. The D-Link website provides general support resources, though specific patch information for affected firmware is not detailed in the CVE data. Security practitioners should consult these references for mitigation guidance and verify firmware updates beyond 20260205. An exploit has been publicly released, increasing the risk of active exploitation.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-12277
Vulnerability Data
A flaw has been found 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. The affected element is the function cgi_myfavorite_add/cgi_myfavorite_set/cgi_myfavorite_del/cgi_myfavorite_set_sort_info/cgi_myfavorite_remove_apkg/cgi_myfavorite_compare_apkg/cgi_mycloud_auto_downlaod of the…
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file /cgi-bin/gui_mgr.cgi. This manipulation of the argument f_user causes command injection. Remote exploitation of the attack is possible. The exploit has been published and may be used.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover command-construction flaws before deployment.
SI-10 directly requires validation of information inputs to reject malformed or special-element content before it reaches downstream parsers.
Secure engineering principles include proper neutralization and safe command construction practices.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly require input validation and output encoding that prevent injection flaws.
Runtime monitoring of software and data can detect anomalous command execution resulting from injection.
Identifying recorded vulnerabilities enables remediation of command-injection flaws before exploitation.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Secure coding standards require proper escaping and parameterization of commands, directly eliminating CWE-77.
Security testing in development catches injection vulnerabilities before release.
Logging supports detection of injection attempts but does not prevent the weakness.
Monitoring activities can identify active injection attacks after they occur.
Secure development life cycle mandates input validation and output encoding that directly prevent injection flaws.
Application security requirements explicitly call for controls against injection attacks in software design.