{"schema_version":"1.7.5","id":"GHSA-99hj-44vg-hfcp","published":"2026-03-27T18:17:42Z","modified":"2026-04-02T21:26:16.462648329Z","aliases":["CVE-2026-26061","GO-2026-4889"],"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.","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":"4.43.5-0.20260113202849-bbc1aef2987d"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-99hj-44vg-hfcp/GHSA-99hj-44vg-hfcp.json"}}],"references":[{"type":"WEB","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"}],"database_specific":{"cwe_ids":["CWE-770"],"github_reviewed":true,"github_reviewed_at":"2026-03-27T18:17:42Z","nvd_published_at":"2026-03-27T19:16:42Z","severity":"HIGH"},"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"}]}