{"cve":"CVE-2026-72817","nvd":{"published":"2026-08-14T12:16:44.747","modified":"2026-10-08T16:17:35.923","status":"Deferred","description":"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.","cvss_v4":{"vector":"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","score":6.9},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","score":6.5},"cwes":["CWE-345"],"references":["https://github.com/go-chi/chi/security/advisories/GHSA-9g5q-2w5x-hmxf","https://www.vulncheck.com/advisories/go-chi-chi-before-ip-spoofing-via-x-forwarded-for"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:48:17.459049833+00:00"},"epss":{"cve":"CVE-2026-72817","score":0.00242,"percentile":0.15199,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-9g5q-2w5x-hmxf","url":"https://osv.dev/vulnerability/GHSA-9g5q-2w5x-hmxf","summary":"chi Middleware Vulnerable to Potential IP Spoofing via `X-Forwarded-For` Header in `Request.RemoteAddr` Resolution","modified":"2026-09-10T03:50:49.185556459Z","packages":[{"ecosystem":"Go","name":"github.com/go-chi/chi/middleware","purl":"pkg:golang/github.com/go-chi/chi/middleware","ranges":[">=0.9.0 <=1.5.5"],"fixed":[]},{"ecosystem":"Go","name":"github.com/go-chi/chi/v2/middleware","purl":"pkg:golang/github.com/go-chi/chi/v2/middleware","ranges":["<=2.1.1"],"fixed":[]},{"ecosystem":"Go","name":"github.com/go-chi/chi/v3/middleware","purl":"pkg:golang/github.com/go-chi/chi/v3/middleware","ranges":["<=3.3.5"],"fixed":[]},{"ecosystem":"Go","name":"github.com/go-chi/chi/v4/middleware","purl":"pkg:golang/github.com/go-chi/chi/v4/middleware","ranges":["<=4.1.3"],"fixed":[]},{"ecosystem":"Go","name":"github.com/go-chi/chi/v5/middleware","purl":"pkg:golang/github.com/go-chi/chi/v5/middleware","ranges":["<5.3.0"],"fixed":["5.3.0"]}]},{"id":"GO-2026-5775","url":"https://osv.dev/vulnerability/GO-2026-5775","summary":"Chi Middleware vulnerable to IP spoofing via X-Forwarded-For header in github.com/go-chi/chi","modified":"2026-08-15T05:19:13.029024907Z","packages":[{"ecosystem":"Go","name":"github.com/go-chi/chi/v5","purl":"pkg:golang/github.com/go-chi/chi/v5","ranges":["<5.3.0"],"fixed":["5.3.0"]}]}],"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."]}