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.
{
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43634.json",
"cna_assigner": "VulnCheck",
"cwe_ids": [
"CWE-348"
]
}