{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "1.2.0"
              },
              {
                "fixed": "1.9.4"
              }
            ],
            "source": [
              "DESCRIPTION",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "8e399f2ab2227dd31d38cebebb738b163534c8d5"
            },
            {
              "fixed": "aae8b2b40bf78fe571d12d49f3a2e5b5ada7d38e"
            },
            {
              "fixed": "f381e294500f671cf12716c638afd0bfde901f88"
            }
          ],
          "repo": "https://github.com/hestiacp/hestiacp",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
      "CWE-348"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43634.json"
  },
  "details": "HestiaCP versions 1.2.0 through 1.9.4 contain an IP spoofing vulnerability that allows unauthenticated remote attackers to bypass authentication security controls by supplying an arbitrary IP address in the CF-Connecting-IP HTTP header without verifying the request originated from Cloudflare's network. Attackers can exploit this to circumvent fail2ban brute-force protection, bypass per-user IP allowlists, and poison authentication audit logs by spoofing trusted IP addresses on each request.",
  "id": "CVE-2026-43634",
  "modified": "2026-07-08T05:39:28.648789218Z",
  "published": "2026-05-19T13:33:08.825Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43634.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43634"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/hestiacp-ip-spoofing-via-cf-connecting-ip-header"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/hestiacp/hestiacp/issues/5229"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/hestiacp/hestiacp/pull/5273"
    },
    {
      "type": "FIX",
      "url": "https://github.com/hestiacp/hestiacp/commit/f381e294500f671cf12716c638afd0bfde901f88"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/hestiacp/hestiacp"
    },
    {
      "type": "EVIDENCE",
      "url": "https://mercuryiss.com.au/hestiacp-unauthenticated-rce-ip-spoofing-cve-2026-43633-cve-2026-43634"
    }
  ],
  "schema_version": "1.7.5",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "HestiaCP 1.2.0-1.9.4 IP Spoofing via CF-Connecting-IP Header"
}