{"id":"CVE-2026-72816","aliases":["GHSA-rjr7-jggh-pgcp","GO-2026-5777"],"url":"https://o3.security/vulnerability/CVE-2026-72816","summary":"go-chi chi before 5.3.0 IP Spoofing via RealIP Middleware","details":"go-chi/chi through 5.2.1 contains an IP spoofing vulnerability in the RealIP middleware (middleware/realip.go). The realIP() function reads client-controlled headers (True-Client-IP, X-Real-IP, and X-Forwarded-For) and overwrites r.RemoteAddr without verifying that the request originated from a trusted proxy. Attackers can supply arbitrary IP addresses in these headers to bypass IP-based access controls, evade rate limiting and geo-IP restrictions, and pollute audit logs. Fixed in 5.3.0.","published":"2026-08-14T11:35:28.145Z","modified":"2026-08-28T17:40:53.206808056Z","cvss":null,"epss":{"score":0.00219,"percentile":0.12298,"asOf":"2026-09-07"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/go-chi/chi/middleware","fixedVersion":null},{"ecosystem":"Go","name":"github.com/go-chi/chi/v2/middleware","fixedVersion":null},{"ecosystem":"Go","name":"github.com/go-chi/chi/v3/middleware","fixedVersion":null},{"ecosystem":"Go","name":"github.com/go-chi/chi/v4/middleware","fixedVersion":null},{"ecosystem":"Go","name":"github.com/go-chi/chi/v5/middleware","fixedVersion":"5.3.0"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72816.json"},{"type":"ADVISORY","url":"https://github.com/go-chi/chi/security/advisories/GHSA-rjr7-jggh-pgcp"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72816"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/go-chi-chi-before-ip-spoofing-via-realip-middleware"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-28T17:40:53.206808056Z"}}