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Medium

go-chi chi 0.9.0 before 5.3.0 IP Spoofing via X-Forwarded-For

Type: advisorySources: OSV

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.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-72817
Confirmed fixed CVEs
Not specified
Updated in this feed
4 Nov 2026, 07:55 UTC · Revision 1

Source evidence

go-chi chi 0.9.0 before 5.3.0 IP Spoofing via X-Forwarded-For

core-osv · Original source

Published 14 Aug 2026, 11:35 UTC

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.

osv:CVE-2026-72817
Complete source record
{
  "id": "30b4ae625477c72399d9918eff88c27a666ab30cd10454285368ea92068d298b",
  "url": "https://osv.dev/vulnerability/CVE-2026-72817",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "go-chi chi 0.9.0 before 5.3.0 IP Spoofing via X-Forwarded-For",
    "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 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.",
    "evidence": "osv:CVE-2026-72817",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-72817",
      "aliases": [
        "CVE-2026-72817",
        "GHSA-9g5q-2w5x-hmxf",
        "GO-2026-5775"
      ],
      "metrics": [
        {
          "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"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/go-chi/chi",
              "type": "GIT",
              "events": [
                {
                  "introduced": "c420d7fbf4428b27e31d83591e5e2267d84f9f20"
                },
                {
                  "fixed": "3b171578ca44dfd75ca3c5cbddc7b44c600a7b49"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0.9.0"
                      },
                      {
                        "fixed": "5.3.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0.9.0"
                      },
                      {
                        "fixed": "5.3.0"
                      }
                    ],
                    "source": "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"
          }
        }
      ],
      "modified": "2026-10-28T02:30:33.773884778Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72817.json",
        "https://github.com/go-chi/chi/security/advisories/GHSA-9g5q-2w5x-hmxf",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-72817",
        "https://www.vulncheck.com/advisories/go-chi-chi-before-ip-spoofing-via-x-forwarded-for"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-345"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72817.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-72817",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 501005,
  "published_at": "2026-08-14T11:35:28.824+00:00"
}