Public proof of concept

CVE-2026-4204

A public proof of concept exists; no exploitation attested.

Published2026-03-16
WeaknessCWE-74 · CWE-77

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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 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.

Timeline

dates in UTC

2026-03-1614:20CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-4204?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-4204?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Dlink dnr-202l firmwareversion to verify

Branch	Affected	Fixed in	Source
2026.x	≤ 2026-02-05	no fix published	NVD

Dlink dnr-326 firmwareversion to verify

Branch	Affected	Fixed in	Source
2026.x	≤ 2026-02-05	no fix published	NVD

Dlink dns-1100-4 firmwareversion to verify

Branch	Affected	Fixed in	Source
2026.x	≤ 2026-02-05	no fix published	NVD

17 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionpoc2026-03-16
OpenCVESSVC decisionpoc—
CNACVSS 4.02.1read 2026-10-23
CNACVSS 3.16.3read 2026-10-23
NVDCVSS 3.19.8read 2026-10-23
CNACVSS 2.06.5read 2026-10-23
CNAweakness (CWE)CWE-74, CWE-77read 2026-10-23
NVDweakness (CWE)CWE-77read 2026-10-23
FIRST EPSSEPSS score5.7 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 4.0 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:X
Published: 2026-03-16
Last Modified: 2026-06-17
NVD status: Analyzed

Frequently asked questions

What is CVE-2026-4204?

Is CVE-2026-4204 actively exploited?

A proof-of-concept exploit exists for CVE-2026-4204, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-4204?

CVE-2026-4204 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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