{"id":"CVE-2026-72817","summary":"go-chi chi 0.9.0 before 5.3.0 IP Spoofing via X-Forwarded-For","details":"go-chi/chi versions 0.9.0 before 5.3.0 contains an IP spoofing vulnerability in the RealIP middleware, which resolves the request source IP (Request.RemoteAddr) using the first IP in the X-Forwarded-For header without validating trusted proxies. A malicious client can prepend a forged IP as the first value of the X-Forwarded-For header to spoof the request source IP, potentially bypassing access controls or falsifying request logs.","aliases":["GHSA-9g5q-2w5x-hmxf","GO-2026-5775"],"modified":"2026-08-19T03:31:02.668525135Z","published":"2026-08-14T11:35:28.824Z","database_specific":{"cwe_ids":["CWE-345"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72817.json","cna_assigner":"VulnCheck"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72817.json"},{"type":"ADVISORY","url":"https://github.com/go-chi/chi/security/advisories/GHSA-9g5q-2w5x-hmxf"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72817"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/go-chi-chi-before-ip-spoofing-via-x-forwarded-for"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/go-chi/chi","events":[{"introduced":"c420d7fbf4428b27e31d83591e5e2267d84f9f20"},{"fixed":"3b171578ca44dfd75ca3c5cbddc7b44c600a7b49"}],"database_specific":{"extracted_events":[{"introduced":"0.9.0"},{"fixed":"5.3.0"}],"source":["AFFECTED_FIELD","DESCRIPTION"]}}],"versions":["v5.2.5","v5.2.4","v5.2.3","v5.2.2","v5.2.1","v5.2.0","v5.1.0","v5.0.14","v5.0.13","v5.0.12","v5.0.11","v4.1.2","v3.3.4","v2.1.0","v1.5.4","v5.0.10","v5.0.9","v5.0.8","v5.0.7","v5.0.6","v5.0.5","v5.0.4","v5.0.3","v5.0.2","v5.0.1","v5.0.0","v1.5.3","v1.5.2","v1.5.1","v4.1.1","v4.1.0","v4.0.4","v4.0.3","v4.0.2","v4.0.1","v4.0.0","v3.3.3","v3.3.2","v3.3.1","v3.3.0","v3.2.1","v3.2.0","v3.1.5","v3.1.4","v3.1.3","v3.1.2","v3.1.1","v3.1.0","v3.0.0","v2.0.0","v1.0.0","v0.9.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72817.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N"}]}