{"answers":{"affected":"3 open source packages ship an affected version, including github.com/fleetdm/fleet/v4. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-23998 in the wild and no public exploit code.","fix":"Upgrade github.com/fleetdm/fleet/v4 to 4.81.0 or later.","what":"CVE-2026-23998 is a high-severity authentication bypass vulnerability in fleetdm fleet, published on 14 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-23998 and fix it if it is affected.\n\nWhat it is: CVE-2026-23998 is a high-severity authentication bypass vulnerability in fleetdm fleet, published on 14 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-23998 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- github.com/fleetdm/fleet/v4 (Go): affected all versions; fixed in 4.81.0\n- github.com/fleetdm/fleet/v4 (Go): affected all versions; fixed in 4.81.0\n- github.com/fleetdm/fleet/v4 (Go): affected all versions; fixed in 4.81.0\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-23998/ (Markdown: https://insights.sbomify.com/CVE-2026-23998/index.md)","id":"CVE-2026-23998","markdown":"https://insights.sbomify.com/CVE-2026-23998/index.md","name":"CVE-2026-23998","record":{"aliases":["GHSA-2rc4-7jc6-qffh","GO-2026-5002"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["data_read","security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Device management software","requires_auth":"none","summary":"Attackers can bypass mTLS authentication to impersonate enrolled Windows devices and retrieve sensitive configuration data from Fleet.","user_interaction":"not_required","vuln_class":"auth_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"fleet","vendor":"fleetdm"}],"cvss":{"score":8.2,"severity":"high","source":"cna","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","version":"4.0"},"cwes":[{"id":"CWE-295","name":"Improper Certificate Validation"}],"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.","ecosystems":["Go"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Fleet has a Windows MDM management endpoint authentication bypass","id":"CVE-2026-23998","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Go","product":null,"products":[],"type":"auth_bypass","year":"2026"},"n_packages":3,"n_references":2,"next":{"headline":"Fleet: Device lock PIN can be predicted if lock time is known","id":"CVE-2026-23999"},"packages":[{"ecosystem":"Go","fixed":["4.81.0"],"introduced":["0"],"last_affected":[],"package":"github.com/fleetdm/fleet/v4","purl":null,"source":"GHSA-2rc4-7jc6-qffh"},{"ecosystem":"Go","fixed":["4.81.0"],"introduced":["0"],"last_affected":[],"package":"github.com/fleetdm/fleet/v4","purl":"pkg:golang/github.com/fleetdm/fleet/v4","source":"GHSA-2rc4-7jc6-qffh"},{"ecosystem":"Go","fixed":["4.81.0"],"introduced":["0"],"last_affected":[],"package":"github.com/fleetdm/fleet/v4","purl":"pkg:golang/github.com/fleetdm/fleet/v4","source":"GO-2026-5002"}],"prev":{"headline":"FacturaScripts has a Stored Cross-Site Scripting (XSS) in \"Observations\" field via History View","id":"CVE-2026-23997"},"products":["fleet"],"published":"2026-05-14","related":[{"cvss_score":10,"headline":"SAML authentication vulnerability in Fleet","id":"CVE-2020-26276","kev_date_added":null,"published":"2020-12-17"},{"cvss_score":9.3,"headline":"Fleet before 4.87.0 Authentication Bypass via Device Identifiers","id":"CVE-2026-103264","kev_date_added":null,"published":"2026-10-01"},{"cvss_score":9.3,"headline":"Fleet has a JWT signature bypass vulnerability in Azure AD MDM enrollment","id":"CVE-2026-23518","kev_date_added":null,"published":"2026-01-21"},{"cvss_score":8.7,"headline":"Fleet server may terminate unexpectedly when handling certain gRPC requests","id":"CVE-2026-26062","kev_date_added":null,"published":"2026-05-14"},{"cvss_score":8.7,"headline":"Fleet's unbounded request body read allows remote Denial of Service","id":"CVE-2026-26061","kev_date_added":null,"published":"2026-03-27"},{"cvss_score":8.2,"headline":"Fleet Windows MDM Azure AD JWT Authentication Bypass","id":"CVE-2026-24899","kev_date_added":null,"published":"2026-05-14"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"Go Vulnerability Database","prefix":"GO"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-05-15","vendors":["fleetdm"]},"summary":"Attackers can bypass mTLS authentication to impersonate enrolled Windows devices and retrieve sensitive configuration data from Fleet.","url":"https://insights.sbomify.com/CVE-2026-23998/"}