{"cve":"CVE-2026-23518","nvd":{"published":"2026-01-21T22:15:50.140","modified":"2026-06-17T10:21:42.850","status":"Analyzed","description":"Fleet is open source device management software. In versions prior to 4.78.3, 4.77.1, 4.76.2, 4.75.2, and 4.53.3, a vulnerability in Fleet's Windows MDM enrollment flow could allow an attacker to submit forged authentication tokens that are not properly validated. Because JWT signatures were not verified, Fleet could accept attacker-controlled identity claims, enabling enrollment of unauthorized devices under arbitrary Azure AD user identities. Versions 4.78.3, 4.77.1, 4.76.2, 4.75.2, and 4.53.3 fix the issue. If an immediate upgrade is not possible, affected Fleet users should temporarily disable Windows MDM.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","score":9.3},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-347"],"references":["https://github.com/fleetdm/fleet/commit/e225ef57912c8f4ac8977e24b5ebe1d9fd875257","https://github.com/fleetdm/fleet/security/advisories/GHSA-63m5-974w-448v"],"products":["fleetdm:fleet"],"source":"nvd","synced_at":"2026-10-19T22:21:16.563232421+00:00"},"epss":{"cve":"CVE-2026-23518","score":0.00254,"percentile":0.17045,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-63m5-974w-448v","url":"https://osv.dev/vulnerability/GHSA-63m5-974w-448v","summary":"Fleet has a JWT signature bypass vulnerability in Azure AD MDM enrollment ","modified":"2026-02-28T06:27:31.335156Z","packages":[{"ecosystem":"Go","name":"github.com/fleetdm/fleet","purl":"pkg:golang/github.com/fleetdm/fleet","ranges":[">=4.78.0 <4.78.3"],"fixed":["4.78.3"]},{"ecosystem":"Go","name":"github.com/fleetdm/fleet","purl":"pkg:golang/github.com/fleetdm/fleet","ranges":[">=4.77.0 <4.77.1"],"fixed":["4.77.1"]},{"ecosystem":"Go","name":"github.com/fleetdm/fleet","purl":"pkg:golang/github.com/fleetdm/fleet","ranges":[">=4.76.0 <4.76.2"],"fixed":["4.76.2"]},{"ecosystem":"Go","name":"github.com/fleetdm/fleet","purl":"pkg:golang/github.com/fleetdm/fleet","ranges":[">=4.75.0 <4.75.2"],"fixed":["4.75.2"]},{"ecosystem":"Go","name":"github.com/fleetdm/fleet","purl":"pkg:golang/github.com/fleetdm/fleet","ranges":["<4.43.5-0.20260112202845-e225ef57912c"],"fixed":["4.43.5-0.20260112202845-e225ef57912c"]}]},{"id":"GO-2026-4335","url":"https://osv.dev/vulnerability/GO-2026-4335","summary":"Fleet has a JWT signature bypass vulnerability in Azure AD MDM enrollment in github.com/fleetdm/fleet","modified":"2026-02-04T19:07:54Z","packages":[{"ecosystem":"Go","name":"github.com/fleetdm/fleet/v4","purl":"pkg:golang/github.com/fleetdm/fleet/v4","ranges":[">=4.75.0 <4.75.2",">=4.76.0 <4.76.2",">=4.77.0 <4.77.1",">=4.78.0 <4.78.3"],"fixed":["4.75.2","4.76.2","4.77.1","4.78.3"]}]}],"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."]}