{"id":"EUVD-2026-30368","revision":null,"records":[{"revision":"54a605fe09774f268c925c0a6f189148","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-23998","aliases":[],"title":"Fleet has a Windows MDM management endpoint authentication bypass","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.","state":0,"publishedAt":"2026-05-14T18:48:38.765+00:00","modifiedAt":"2026-05-15T14:12:52.682+00:00","affected":[{"ecosystem":"Vendor product","name":"fleet","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"fleetdm\",\n                    \"product\": \"fleet\",\n                    \"versions\": [\n                        {\n                            \"version\": \"< 4.81.0\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 4.0","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,"severity":"HIGH"}],"references":["https://github.com/fleetdm/fleet/security/advisories/GHSA-2rc4-7jc6-qffh","https://github.com/fleetdm/fleet/releases/tag/fleet-v4.81.0"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-23998","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-23998","identifiers":["CVE-2026-23998"]},"retained":false,"historicalAffected":[]},{"revision":"19d3bfeea5264c48a3fb19a814b0b7b2","observedAt":"2026-10-28T02:05:48.624+00:00","statement":{"source":"euvd","id":"EUVD-2026-30368","aliases":["CVE-2026-23998","GHSA-2rc4-7jc6-qffh"],"title":"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…","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.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 4.0","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,"severity":null}],"references":["https://github.com/fleetdm/fleet/security/advisories/GHSA-2rc4-7jc6-qffh","https://github.com/fleetdm/fleet/releases/tag/fleet-v4.81.0"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-30368","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"May 14, 2026, 6:48:38 PM","dateUpdated":"May 15, 2026, 2:12:52 PM"},"relatedAdvisories":[],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON."},"key":"euvd:EUVD-2026-30368","identifiers":["EUVD-2026-30368","CVE-2026-23998","GHSA-2rc4-7jc6-qffh"]},"retained":false,"historicalAffected":[]},{"revision":"3c6ae7dc847d47258c6af18ae01f6c61","observedAt":"2026-10-27T06:23:38.127+00:00","statement":{"source":"nvd","id":"CVE-2026-23998","aliases":[],"title":"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…","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.","state":0,"publishedAt":"2026-05-14T19:16:30.983+00:00","modifiedAt":"2026-10-26T14:10:00.13+00:00","affected":[],"metrics":[{"system":"CVSS 4.0 · security-advisories@github.com · Secondary","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/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","score":8.2,"severity":"HIGH"},{"system":"CVSS 3.1 · nvd@nist.gov · Primary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","score":7.5,"severity":"HIGH"}],"references":["https://github.com/fleetdm/fleet/releases/tag/fleet-v4.81.0","https://github.com/fleetdm/fleet/security/advisories/GHSA-2rc4-7jc6-qffh"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-23998","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Analyzed","weaknesses":["CWE-295"],"productCriteria":["cpe:2.3:a:fleetdm:fleet:*:*:*:*:*:*:*:*"],"sourceDates":{"published":"2026-05-14T19:16:30.983","lastModified":"2026-10-26T14:10:00.130"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-23998","identifiers":["CVE-2026-23998"]},"retained":false,"historicalAffected":[]},{"revision":"f874c00c0a6e4f758ebbc9ea8da76b25","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GHSA-2rc4-7jc6-qffh","aliases":["CVE-2026-23998","GO-2026-5002"],"title":"Fleet has a Windows MDM management endpoint authentication bypass","description":"### Summary\n\nA 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.\n\n### Impact\n\nFleet’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.\n\nAs 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.\n\nThis 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.\n\n### Workarounds\n\nIf an immediate upgrade is not possible, affected Fleet users should temporarily disable Windows MDM.\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n\nEmail us at [security@fleetdm.com](mailto:security@fleetdm.com)\nJoin #fleet in [osquery Slack](https://join.slack.com/t/osquery/shared_invite/zt-h29zm0gk-s2DBtGUTW4CFel0f0IjTEw)\n\n### Credits\n\nWe thank @secfox-ai for responsibly reporting this issue.","state":0,"publishedAt":"2026-05-14T13:13:11+00:00","modifiedAt":"2026-06-08T23:45:19.1729642+00:00","affected":[{"ecosystem":"Go","name":"github.com/fleetdm/fleet/v4","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"4.81.0"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","score":null,"severity":null},{"system":"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":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"HIGH"}],"references":["https://github.com/fleetdm/fleet/security/advisories/GHSA-2rc4-7jc6-qffh","https://nvd.nist.gov/vuln/detail/CVE-2026-23998","https://github.com/fleetdm/fleet/commit/3ff8119ab8f794806a4cc82e21f760c123d92966","https://github.com/fleetdm/fleet","https://github.com/fleetdm/fleet/releases/tag/fleet-v4.81.0"],"sourceUrl":"https://github.com/advisories/GHSA-2rc4-7jc6-qffh","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-2rc4-7jc6-qffh","identifiers":["GHSA-2rc4-7jc6-qffh","CVE-2026-23998","GO-2026-5002"]},"retained":false,"historicalAffected":[]},{"revision":"010d71bac6464b8182e4fca2b7c7c449","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GO-2026-5002","aliases":["CVE-2026-23998","GHSA-2rc4-7jc6-qffh"],"title":"Windows MDM management endpoint authentication bypass in github.com/fleetdm/fleet/v4","description":"Windows MDM management endpoint authentication bypass in github.com/fleetdm/fleet/v4","state":0,"publishedAt":"2026-05-26T22:48:34+00:00","modifiedAt":"2026-05-26T23:15:13.6397122+00:00","affected":[{"ecosystem":"Go","name":"github.com/fleetdm/fleet/v4","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"4.81.0"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[],"references":["https://github.com/fleetdm/fleet/security/advisories/GHSA-2rc4-7jc6-qffh","https://github.com/fleetdm/fleet/commit/3ff8119ab8f794806a4cc82e21f760c123d92966"],"sourceUrl":"https://osv.dev/vulnerability/GO-2026-5002","license":"OSV · upstream source license applies","key":"osv:GO-2026-5002","identifiers":["GO-2026-5002","CVE-2026-23998","GHSA-2rc4-7jc6-qffh"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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