{"id":"GHSA-j8h8-75h3-jg53","summary":"Fleet has a rate limiting bypass via untrusted client IP headers","details":"### Impact\n\nFleet trusted client-supplied IP address headers when determining the source IP for incoming requests. This allowed authenticated and unauthenticated clients to spoof their apparent IP address and bypass per-IP rate limiting controls.\n\nFleet determines a client’s public IP address using HTTP headers such as:\n- X-Forwarded-For\n- X-Real-IP\n- True-Client-IP\n\nThese headers were trusted without validation. An attacker could supply arbitrary values in these headers, causing Fleet to treat each request as originating from a different IP address.\n\nThis could allow an attacker to bypass per-IP rate limits and increase the effectiveness of brute-force or password-spraying attempts against authentication endpoints.\n\nThis issue does not allow authentication bypass, privilege escalation, data exposure, or remote code execution on its own.\n\n### Workarounds\n\nRun Fleet behind a trusted reverse proxy or load balancer that overwrites client IP headers.\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n\nEmail us at [security@fleetdm.com](mailto:security@fleetdm.com)\nJoin #fleet in [osquery Slack](https://join.slack.com/t/osquery/shared_invite/zt-h29zm0gk-s2DBtGUTW4CFel0f0IjTEw)\n\n### Credits\n\nWe thank @fuzzztf for responsibly reporting this issue.","aliases":["CVE-2026-24000","GO-2026-5455"],"modified":"2026-06-25T23:11:31.673819281Z","published":"2026-05-14T13:13:39Z","database_specific":{"nvd_published_at":"2026-05-14T20:17:01Z","cwe_ids":["CWE-290"],"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2026-05-14T13:13:39Z"},"references":[{"type":"WEB","url":"https://github.com/fleetdm/fleet/security/advisories/GHSA-j8h8-75h3-jg53"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-24000"},{"type":"PACKAGE","url":"https://github.com/fleetdm/fleet"},{"type":"WEB","url":"https://github.com/fleetdm/fleet/releases/tag/fleet-v4.80.1"}],"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":"4.80.1"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-j8h8-75h3-jg53/GHSA-j8h8-75h3-jg53.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N"}]}