{"id":"GHSA-x67p-9m2r-fxqv","summary":"Fleet server may terminate unexpectedly when handling certain gRPC requests","details":"### Summary\n\nFleet contained a denial-of-service (DoS) issue in the gRPC Launcher `PublishLogs` endpoint. In affected versions, certain unexpected input values were not handled gracefully, which could cause the Fleet server process to terminate while processing an authenticated request from an enrolled Launcher host.\n\n### Impact\n\nAn authenticated attacker with access to any enrolled Launcher node key could cause an immediate and complete denial of service by sending a single gRPC request to the `PublishLogs` endpoint.\n\nThis vulnerability impacts **availability only**. There is:\n\n- No exposure of sensitive data\n- No authentication bypass\n- No privilege escalation\n- No integrity impact\n\n### Workarounds\n\nIf upgrading immediately is not possible, the following mitigations can reduce exposure:\n\n- Restrict network access to the Fleet gRPC endpoint where feasible (for example, limiting inbound access to known host IP ranges).\n- Deploy Fleet behind infrastructure that terminates or filters gRPC traffic if Launcher log ingestion is not required.\n- Monitor for repeated Fleet process crashes or unexpected restarts indicating potential exploitation.\n\n### For More Information\n\nIf you have any questions or concerns about this advisory, please contact us at:\n\nEmail us at [security@fleetdm.com](mailto:security@fleetdm.com)\n\n### Credits\n\nWe thank @fuzzztf for responsibly reporting this issue.","aliases":["CVE-2026-26062","GO-2026-5744"],"modified":"2026-06-25T23:11:26.904886359Z","published":"2026-05-14T13:17:18Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2026-05-14T13:17:18Z","nvd_published_at":"2026-05-14T20:17:02Z","cwe_ids":["CWE-20"],"severity":"HIGH"},"references":[{"type":"WEB","url":"https://github.com/fleetdm/fleet/security/advisories/GHSA-x67p-9m2r-fxqv"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-26062"},{"type":"PACKAGE","url":"https://github.com/fleetdm/fleet"},{"type":"WEB","url":"https://github.com/fleetdm/fleet/releases/tag/fleet-v4.81.0"}],"affected":[{"package":{"name":"github.com/fleetdm/fleet/v4","ecosystem":"Go","purl":"pkg:golang/github.com/fleetdm/fleet/v4"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.81.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-x67p-9m2r-fxqv/GHSA-x67p-9m2r-fxqv.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"}]}