GHSA-99hj-44vg-hfcp Fleet's unbounded request body read allows remote Denial of Service

• Go github.com/fleetdm/fleet/v4: < 4.43.5-0.20260113202849-bbc1aef2987d → fixed in 4.43.5-0.20260113202849-bbc1aef2987d

Summary Fleet 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. Impact An unauthenticated attacker could cause the Fleet server process to exhaust available memory and restart by sending oversized or repeated HTTP requests to affected endpoints. This vulnerability impacts availability only. There is: • No exposure of sensitive data • No authentication bypass • No privilege escalation • No integrity impact Workarounds If upgrading immediately is not possible, the following mitigations can reduce exposure: • Apply request body size limits at a reverse proxy or load balancer (e.g., NGINX, Envoy). • Restrict network access to endpoints to known IP ranges where feasible. • Monitor memory usage and restart frequency for abnormal patterns. For More Information If there are any questions or concerns about this advisory, please contact us at: Email Fleet at [email protected] Credits Fleet thanks @fuzzztf for responsibly reporting this issue.