Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| hestiacp | hestiacp | 1.2.0 – ≤ 1.9.4 | — |
References
- https://mercuryiss.com.au/hestiacp-unauthenticated-rce-ip-spoofing-cve-2026-43633-cve-2026-43634 technical-description exploit
- https://github.com/hestiacp/hestiacp/issues/5229 issue-tracking
- https://github.com/hestiacp/hestiacp/pull/5273 issue-tracking patch
- https://github.com/hestiacp/hestiacp/commit/f381e294500f671cf12716c638afd0bfde901f88 patch
- https://www.vulncheck.com/advisories/hestiacp-ip-spoofing-via-cf-connecting-ip-header third-party-advisory