{"id":"CVE-2026-24000","aliases":["GHSA-j8h8-75h3-jg53","GO-2026-5455"],"url":"https://o3.security/vulnerability/CVE-2026-24000","summary":"Fleet has a rate limiting bypass via untrusted client IP headers","details":"Fleet is open source device management software. Prior to version 4.80.1, Fleet 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. Fleet determines a client’s public IP address using HTTP headers such as X-Forwarded-For, X-Real-IP, and/or True-Client-IP. These 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. This could allow an attacker to bypass per-IP rate limits and increase the effectiveness of brute-force or password-spraying attempts against authentication endpoints. This issue does not allow authentication bypass, privilege escalation, data exposure, or remote code execution on its own. Version 4.80.1 contains a patch. As a workaround, run Fleet behind a trusted reverse proxy or load balancer that overwrites client IP headers.","published":"2026-05-14T18:56:39.139Z","modified":"2026-08-05T03:32:27.158031542Z","cvss":null,"epss":{"score":0.0043,"percentile":0.35403,"asOf":"2026-08-10"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/fleetdm/fleet/v4","fixedVersion":"4.80.1"}],"fix":null,"references":[{"type":"WEB","url":"https://github.com/fleetdm/fleet/releases/tag/fleet-v4.80.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/24xxx/CVE-2026-24000.json"},{"type":"ADVISORY","url":"https://github.com/fleetdm/fleet/security/advisories/GHSA-j8h8-75h3-jg53"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-24000"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-05T03:32:27.158031542Z"}}