{"answers":{"affected":"11 open source packages ship an affected version, including github.com/fleetdm/fleet and github.com/fleetdm/fleet/v4. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-23518 in the wild and no public exploit code.","fix":"Upgrade github.com/fleetdm/fleet to a fixed version for your release line: 4.43.5-0.20260112202845-e225ef57912c, 4.75.2, 4.76.2 or 4.77.1.","what":"CVE-2026-23518 is a critical authentication bypass vulnerability in fleetdm fleet, published on 21 Jan 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-2026-23518 and fix it if it is affected.\n\nWhat it is: CVE-2026-23518 is a critical authentication bypass vulnerability in fleetdm fleet, published on 21 Jan 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-2026-23518 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- github.com/fleetdm/fleet (Go): affected all versions; fixed in 4.43.5-0.20260112202845-e225ef57912c\n- github.com/fleetdm/fleet (Go): affected all versions; fixed in 4.43.5-0.20260112202845-e225ef57912c\n- github.com/fleetdm/fleet (Go): affected from 4.75.0; fixed in 4.75.2\n- github.com/fleetdm/fleet (Go): affected from 4.75.0; fixed in 4.75.2\n- github.com/fleetdm/fleet (Go): affected from 4.76.0; fixed in 4.76.2\n- github.com/fleetdm/fleet (Go): affected from 4.76.0; fixed in 4.76.2\n- github.com/fleetdm/fleet (Go): affected from 4.77.0; fixed in 4.77.1\n- github.com/fleetdm/fleet (Go): affected from 4.77.0; fixed in 4.77.1\n- github.com/fleetdm/fleet (Go): affected from 4.78.0; fixed in 4.78.3\n- github.com/fleetdm/fleet (Go): affected from 4.78.0; fixed in 4.78.3\n- github.com/fleetdm/fleet/v4 (Go): affected from 4.75.0; fixed in 4.75.2, 4.76.2, 4.77.1, 4.78.3\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-2026-23518/ (Markdown: https://insights.sbomify.com/CVE-2026-23518/index.md)","id":"CVE-2026-23518","markdown":"https://insights.sbomify.com/CVE-2026-23518/index.md","name":"CVE-2026-23518","record":{"aliases":["GHSA-63m5-974w-448v","GO-2026-4335"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["privilege_escalation","security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Device management software","requires_auth":"none","summary":"Attackers can forge JWT tokens to enroll unauthorized devices under arbitrary user identities due to missing signature verification in Fleet's Windows MDM enrollment.","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":9.3,"severity":"critical","source":"cna","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","version":"4.0"},"cwes":[{"id":"CWE-347","name":"Improper Verification of Cryptographic Signature"}],"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.","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 JWT signature bypass vulnerability in Azure AD MDM enrollment","id":"CVE-2026-23518","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Go","product":null,"products":[],"type":"auth_bypass","year":"2026"},"n_packages":11,"n_references":2,"next":{"headline":"RustCrypto cmov: thumbv6m-none-eabi compiler emits non-constant time assembly when using cmovnz","id":"CVE-2026-23519"},"packages":[{"ecosystem":"Go","fixed":["4.43.5-0.20260112202845-e225ef57912c"],"introduced":["0"],"last_affected":[],"package":"github.com/fleetdm/fleet","purl":null,"source":"GHSA-63m5-974w-448v"},{"ecosystem":"Go","fixed":["4.43.5-0.20260112202845-e225ef57912c"],"introduced":["0"],"last_affected":[],"package":"github.com/fleetdm/fleet","purl":"pkg:golang/github.com/fleetdm/fleet","source":"GHSA-63m5-974w-448v"},{"ecosystem":"Go","fixed":["4.75.2"],"introduced":["4.75.0"],"last_affected":[],"package":"github.com/fleetdm/fleet","purl":null,"source":"GHSA-63m5-974w-448v"},{"ecosystem":"Go","fixed":["4.75.2"],"introduced":["4.75.0"],"last_affected":[],"package":"github.com/fleetdm/fleet","purl":"pkg:golang/github.com/fleetdm/fleet","source":"GHSA-63m5-974w-448v"},{"ecosystem":"Go","fixed":["4.76.2"],"introduced":["4.76.0"],"last_affected":[],"package":"github.com/fleetdm/fleet","purl":null,"source":"GHSA-63m5-974w-448v"},{"ecosystem":"Go","fixed":["4.76.2"],"introduced":["4.76.0"],"last_affected":[],"package":"github.com/fleetdm/fleet","purl":"pkg:golang/github.com/fleetdm/fleet","source":"GHSA-63m5-974w-448v"},{"ecosystem":"Go","fixed":["4.77.1"],"introduced":["4.77.0"],"last_affected":[],"package":"github.com/fleetdm/fleet","purl":null,"source":"GHSA-63m5-974w-448v"},{"ecosystem":"Go","fixed":["4.77.1"],"introduced":["4.77.0"],"last_affected":[],"package":"github.com/fleetdm/fleet","purl":"pkg:golang/github.com/fleetdm/fleet","source":"GHSA-63m5-974w-448v"},{"ecosystem":"Go","fixed":["4.78.3"],"introduced":["4.78.0"],"last_affected":[],"package":"github.com/fleetdm/fleet","purl":null,"source":"GHSA-63m5-974w-448v"},{"ecosystem":"Go","fixed":["4.78.3"],"introduced":["4.78.0"],"last_affected":[],"package":"github.com/fleetdm/fleet","purl":"pkg:golang/github.com/fleetdm/fleet","source":"GHSA-63m5-974w-448v"},{"ecosystem":"Go","fixed":["4.75.2","4.76.2","4.77.1","4.78.3"],"introduced":["4.75.0","4.76.0","4.77.0","4.78.0"],"last_affected":[],"package":"github.com/fleetdm/fleet/v4","purl":"pkg:golang/github.com/fleetdm/fleet/v4","source":"GO-2026-4335"}],"prev":{"headline":"Fleet has an Access Control vulnerability in debug/pprof endpoints","id":"CVE-2026-23517"},"products":["fleet"],"published":"2026-01-21","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":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 has a Windows MDM management endpoint authentication bypass","id":"CVE-2026-23998","kev_date_added":null,"published":"2026-05-14"},{"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":"yes","exploitation":"none","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-01-22","vendors":["fleetdm"]},"summary":"Attackers can forge JWT tokens to enroll unauthorized devices under arbitrary user identities due to missing signature verification in Fleet's Windows MDM enrollment.","url":"https://insights.sbomify.com/CVE-2026-23518/"}