{"cve":"CVE-2026-23998","nvd":{"published":"2026-05-14T19:16:30.983","modified":"2026-10-26T14:10:00.130","status":"Analyzed","description":"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.","cvss_v4":{"vector":"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","score":8.2},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","score":7.5},"cwes":["CWE-295"],"references":["https://github.com/fleetdm/fleet/releases/tag/fleet-v4.81.0","https://github.com/fleetdm/fleet/security/advisories/GHSA-2rc4-7jc6-qffh"],"products":["fleetdm:fleet"],"source":"nvd","synced_at":"2026-10-26T14:27:29.784594657+00:00"},"epss":{"cve":"CVE-2026-23998","score":0.00214,"percentile":0.11704,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-2rc4-7jc6-qffh","url":"https://osv.dev/vulnerability/GHSA-2rc4-7jc6-qffh","summary":"Fleet has a Windows MDM management endpoint authentication bypass","modified":"2026-06-08T23:45:19.172964221Z","packages":[{"ecosystem":"Go","name":"github.com/fleetdm/fleet/v4","purl":"pkg:golang/github.com/fleetdm/fleet/v4","ranges":["<4.81.0"],"fixed":["4.81.0"]}]},{"id":"GO-2026-5002","url":"https://osv.dev/vulnerability/GO-2026-5002","summary":"Windows MDM management endpoint authentication bypass in github.com/fleetdm/fleet/v4","modified":"2026-05-26T23:15:13.639712222Z","packages":[{"ecosystem":"Go","name":"github.com/fleetdm/fleet/v4","purl":"pkg:golang/github.com/fleetdm/fleet/v4","ranges":["<4.81.0"],"fixed":["4.81.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}