{"id":"CVE-2026-26062","aliases":["GHSA-x67p-9m2r-fxqv","GO-2026-5744"],"url":"https://o3.security/vulnerability/CVE-2026-26062","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.","published":"2026-05-14T19:00:21.559Z","modified":"2026-08-12T03:51:46.315965146Z","cvss":null,"epss":{"score":0.00372,"percentile":0.29887,"asOf":"2026-08-24"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/fleetdm/fleet/v4","fixedVersion":"4.81.0"}],"fix":null,"references":[{"type":"WEB","url":"https://github.com/fleetdm/fleet/releases/tag/fleet-v4.81.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/26xxx/CVE-2026-26062.json"},{"type":"ADVISORY","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"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:46.315965146Z"}}