{"id":"CVE-2026-72817","title":"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 …","summary":"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 …","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","cwe":["CWE-345"],"vendor":"go-chi","product":"github.com/go-chi/chi/middleware","affected":["github.com/go-chi/chi/middleware >= 0.9.0, <= 1.5.5","github.com/go-chi/chi/v2/middleware <= 2.1.1","github.com/go-chi/chi/v3/middleware <= 3.3.5","github.com/go-chi/chi/v4/middleware <= 4.1.3","github.com/go-chi/chi/v5/middleware < 5.3.0"],"patched":["github.com/go-chi/chi/v5/middleware 5.3.0"],"published":"2026-08-14","updated":"2026-09-09","sourceUpdated":"2026-09-09T20:35:08.537","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-72817","references":[{"url":"https://github.com/go-chi/chi/security/advisories/GHSA-9g5q-2w5x-hmxf","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/go-chi-chi-before-ip-spoofing-via-x-forwarded-for","label":"disclosure@vulncheck.com"},{"url":"https://github.com/go-chi/chi"},{"url":"https://github.com/go-chi/chi/releases/tag/v5.3.0"}],"tags":["nvd","osv","go"],"epss":0.00242,"epssPercentile":0.13695,"aliases":["GHSA-9g5q-2w5x-hmxf","GO-2026-5775"],"ecosystem":"go","ingestedAt":"2026-08-15T19:19:53.710Z","slug":"CVE-2026-72817","body":"## Overview\n\ngo-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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-72817)\n\nAffected packages:\n\n- `github.com/go-chi/chi/middleware >= 0.9.0, <= 1.5.5`\n- `github.com/go-chi/chi/v2/middleware <= 2.1.1`\n- `github.com/go-chi/chi/v3/middleware <= 3.3.5`\n- `github.com/go-chi/chi/v4/middleware <= 4.1.3`\n- `github.com/go-chi/chi/v5/middleware < 5.3.0`\n\nPatched in:\n\n- `github.com/go-chi/chi/v5/middleware 5.3.0`\n\nSource: https://osv.dev/vulnerability/GHSA-9g5q-2w5x-hmxf","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":201895,"id":"CVE-2026-72817","ts":1789399974137,"field":"cvss","old":null,"new":"6.5"},{"seq":201894,"id":"CVE-2026-72817","ts":1789399974137,"field":"severity","old":"high","new":"medium"},{"seq":200625,"id":"CVE-2026-72817","ts":1789397537311,"field":"cvss","old":"6.5","new":null},{"seq":200624,"id":"CVE-2026-72817","ts":1789397537311,"field":"severity","old":"medium","new":"high"},{"seq":199339,"id":"CVE-2026-72817","ts":1789395455786,"field":"cvss","old":null,"new":"6.5"},{"seq":199338,"id":"CVE-2026-72817","ts":1789395455786,"field":"severity","old":"high","new":"medium"},{"seq":198584,"id":"CVE-2026-72817","ts":1789392135732,"field":"cvss","old":"6.5","new":null},{"seq":198583,"id":"CVE-2026-72817","ts":1789392135732,"field":"severity","old":"medium","new":"high"},{"seq":198539,"id":"CVE-2026-72817","ts":1789392062937,"field":"cvss","old":null,"new":"6.5"},{"seq":198538,"id":"CVE-2026-72817","ts":1789392062937,"field":"severity","old":"high","new":"medium"},{"seq":196330,"id":"CVE-2026-72817","ts":1789383702619,"field":"cvss","old":"6.5","new":null},{"seq":196329,"id":"CVE-2026-72817","ts":1789383702619,"field":"severity","old":"medium","new":"high"},{"seq":195259,"id":"CVE-2026-72817","ts":1789380539631,"field":"cvss","old":null,"new":"6.5"},{"seq":195258,"id":"CVE-2026-72817","ts":1789380539631,"field":"severity","old":"high","new":"medium"},{"seq":194046,"id":"CVE-2026-72817","ts":1789378648921,"field":"cvss","old":"6.5","new":null},{"seq":194045,"id":"CVE-2026-72817","ts":1789378648921,"field":"severity","old":"medium","new":"high"},{"seq":192833,"id":"CVE-2026-72817","ts":1789376469385,"field":"cvss","old":null,"new":"6.5"},{"seq":192832,"id":"CVE-2026-72817","ts":1789376469385,"field":"severity","old":"high","new":"medium"},{"seq":191620,"id":"CVE-2026-72817","ts":1789373555682,"field":"cvss","old":"6.5","new":null},{"seq":191619,"id":"CVE-2026-72817","ts":1789373555682,"field":"severity","old":"medium","new":"high"},{"seq":190405,"id":"CVE-2026-72817","ts":1789369416982,"field":"cvss","old":null,"new":"6.5"},{"seq":190404,"id":"CVE-2026-72817","ts":1789369416982,"field":"severity","old":"high","new":"medium"},{"seq":189192,"id":"CVE-2026-72817","ts":1789368347332,"field":"cvss","old":"6.5","new":null},{"seq":189191,"id":"CVE-2026-72817","ts":1789368347332,"field":"severity","old":"medium","new":"high"},{"seq":187975,"id":"CVE-2026-72817","ts":1789365200381,"field":"cvss","old":null,"new":"6.5"},{"seq":187974,"id":"CVE-2026-72817","ts":1789365200381,"field":"severity","old":"high","new":"medium"},{"seq":186762,"id":"CVE-2026-72817","ts":1789363411875,"field":"cvss","old":"6.5","new":null},{"seq":186761,"id":"CVE-2026-72817","ts":1789363411875,"field":"severity","old":"medium","new":"high"},{"seq":185548,"id":"CVE-2026-72817","ts":1789361182848,"field":"cvss","old":null,"new":"6.5"},{"seq":185547,"id":"CVE-2026-72817","ts":1789361182848,"field":"severity","old":"high","new":"medium"},{"seq":184335,"id":"CVE-2026-72817","ts":1789358274980,"field":"cvss","old":"6.5","new":null},{"seq":184334,"id":"CVE-2026-72817","ts":1789358274980,"field":"severity","old":"medium","new":"high"},{"seq":182586,"id":"CVE-2026-72817","ts":1789354275896,"field":"cvss","old":null,"new":"6.5"},{"seq":182585,"id":"CVE-2026-72817","ts":1789354275896,"field":"severity","old":"high","new":"medium"},{"seq":181379,"id":"CVE-2026-72817","ts":1789353247994,"field":"cvss","old":"6.5","new":null},{"seq":181378,"id":"CVE-2026-72817","ts":1789353247994,"field":"severity","old":"medium","new":"high"},{"seq":180172,"id":"CVE-2026-72817","ts":1789350228417,"field":"cvss","old":null,"new":"6.5"},{"seq":180171,"id":"CVE-2026-72817","ts":1789350228417,"field":"severity","old":"high","new":"medium"},{"seq":178965,"id":"CVE-2026-72817","ts":1789348224283,"field":"cvss","old":"6.5","new":null},{"seq":178964,"id":"CVE-2026-72817","ts":1789348224283,"field":"severity","old":"medium","new":"high"},{"seq":177758,"id":"CVE-2026-72817","ts":1789346332537,"field":"cvss","old":null,"new":"6.5"},{"seq":177757,"id":"CVE-2026-72817","ts":1789346332537,"field":"severity","old":"high","new":"medium"},{"seq":176551,"id":"CVE-2026-72817","ts":1789343130530,"field":"cvss","old":"6.5","new":null},{"seq":176550,"id":"CVE-2026-72817","ts":1789343130530,"field":"severity","old":"medium","new":"high"},{"seq":174668,"id":"CVE-2026-72817","ts":1789334840633,"field":"cvss","old":null,"new":"6.5"},{"seq":174667,"id":"CVE-2026-72817","ts":1789334840633,"field":"severity","old":"high","new":"medium"},{"seq":173463,"id":"CVE-2026-72817","ts":1789333609219,"field":"cvss","old":"6.5","new":null},{"seq":173462,"id":"CVE-2026-72817","ts":1789333609219,"field":"severity","old":"medium","new":"high"},{"seq":172277,"id":"CVE-2026-72817","ts":1789331056362,"field":"cvss","old":null,"new":"6.5"},{"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