---
id: CVE-2026-43634
title: HestiaCP 1.2.0-1.9.4 IP Spoofing via CF-Connecting-IP Header
summary: >-
  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 w…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'
cvssSource: cna
cwe:
  - CWE-348
vendor: hestiacp
product: hestiacp
affected:
  - hestiacp >= 1.2.0 <= 1.9.4
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-05-19T16:39:12.742374Z'
exploitAvailable: true
published: '2026-05-19'
updated: '2026-11-08'
sourceUpdated: '2026-11-08T14:03:28.605Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-43634'
references:
  - url: >-
      https://mercuryiss.com.au/hestiacp-unauthenticated-rce-ip-spoofing-cve-2026-43633-cve-2026-43634
  - url: 'https://github.com/hestiacp/hestiacp/issues/5229'
  - url: 'https://github.com/hestiacp/hestiacp/pull/5273'
  - url: >-
      https://github.com/hestiacp/hestiacp/commit/f381e294500f671cf12716c638afd0bfde901f88
  - url: >-
      https://www.vulncheck.com/advisories/hestiacp-ip-spoofing-via-cf-connecting-ip-header
tags:
  - cve.org
  - exploit-available
epss: 0.00241
epssPercentile: 0.15295
ingestedAt: '2026-11-08T14:51:22.430Z'
---

## Overview

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

- `hestiacp >= 1.2.0 <= 1.9.4`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.