{"cve":"CVE-2026-46356","nvd":{"published":"2026-05-14T20:17:09.540","modified":"2026-10-26T14:10:00.130","status":"Analyzed","description":"Fleet is open source device management software. Prior to version 4.80.1, a vulnerability in Fleet's IP extraction logic allows unauthenticated attackers to bypass API rate limiting by spoofing client IP headers. This may allow brute-force login attempts or other abuse against Fleet instances exposed to the public internet. Fleet extracted client IP addresses from request headers (`True-Client-IP`, `X-Real-IP`, `X-Forwarded-For`) without validating that those headers originate from a trusted proxy. The extracted IP is used as the key for rate limiting and IP ban decisions. As a result, an attacker could rotate the value of these headers on each request, causing Fleet to treat each attempt as coming from a different client. This effectively bypasses per-IP rate limits on sensitive endpoints such as the login API, enabling unrestricted brute-force or credential stuffing attacks. This issue primarily affects Fleet instances that are directly exposed to the internet without a reverse proxy that overwrites forwarded-IP headers. Instances behind a properly configured proxy or WAF are less affected. Version 4.80.1 contains a patch. If an immediate upgrade is not possible, administrators should ensure Fleet is deployed behind a reverse proxy (e.g., nginx, Cloudflare, AWS ALB) that overwrites `X-Forwarded-For` with the true client IP, and apply rate limiting at the proxy or WAF layer.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","score":6.9},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","score":7.5},"cwes":["CWE-290"],"references":["https://github.com/fleetdm/fleet/releases/tag/fleet-v4.80.1","https://github.com/fleetdm/fleet/security/advisories/GHSA-mxmp-wr3w-rvqx"],"products":["fleetdm:fleet"],"source":"nvd","synced_at":"2026-10-26T14:27:29.784594657+00:00"},"epss":{"cve":"CVE-2026-46356","score":0.00276,"percentile":0.19834,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-mxmp-wr3w-rvqx","url":"https://osv.dev/vulnerability/GHSA-mxmp-wr3w-rvqx","summary":"Fleet: IP spoofing allows bypassing API rate limiting","modified":"2026-06-25T23:11:45.294118568Z","packages":[{"ecosystem":"Go","name":"github.com/fleetdm/fleet/v4","purl":"pkg:golang/github.com/fleetdm/fleet/v4","ranges":["<4.80.1"],"fixed":["4.80.1"]}]},{"id":"GO-2026-5520","url":"https://osv.dev/vulnerability/GO-2026-5520","summary":"Fleet: IP spoofing allows bypassing API rate limiting in github.com/fleetdm/fleet","modified":"2026-06-25T23:01:15.925757398Z","packages":[{"ecosystem":"Go","name":"github.com/fleetdm/fleet/v4","purl":"pkg:golang/github.com/fleetdm/fleet/v4","ranges":["<4.80.1"],"fixed":["4.80.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}