{"id":"CVE-2026-26061","aliases":["GHSA-99hj-44vg-hfcp","GO-2026-4889"],"url":"https://o3.security/vulnerability/CVE-2026-26061","summary":"Fleet's unbounded request body read allows remote Denial of Service","details":"### Summary\n\nFleet contained multiple unauthenticated HTTP endpoints that read request bodies without enforcing a size limit. An unauthenticated attacker could exploit this behavior by sending large or repeated HTTP payloads, causing excessive memory allocation and resulting in a denial-of-service (DoS) condition.\n\n### Impact\n\nAn unauthenticated attacker could cause the Fleet server process to exhaust available memory and restart by sending oversized or repeated HTTP requests to affected endpoints.\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- Apply request body size limits at a reverse proxy or load balancer (e.g., NGINX, Envoy).\n- Restrict network access to endpoints to known IP ranges where feasible.\n- Monitor memory usage and restart frequency for abnormal patterns.\n\n### For More Information\n\nIf there are any questions or concerns about this advisory, please contact us at:\n\nEmail Fleet at [security@fleetdm.com](mailto:security@fleetdm.com)\n\n### Credits\n\nFleet thanks @fuzzztf for responsibly reporting this issue.","published":"2026-03-27T18:23:49.791Z","modified":"2026-08-12T03:51:15.007951389Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/fleetdm/fleet/v4","fixedVersion":"4.43.5-0.20260113202849-bbc1aef2987d"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/26xxx/CVE-2026-26061.json"},{"type":"ADVISORY","url":"https://github.com/fleetdm/fleet/security/advisories/GHSA-99hj-44vg-hfcp"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-26061"},{"type":"PACKAGE","url":"https://github.com/fleetdm/fleet"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:15.007951389Z"}}