CVE-2026-43634
HestiaCP 1.2.0-1.9.4 IP Spoofing via CF-Connecting-IP Header
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-348 |
| Vendor | hestiacp |
| Product | hestiacp |
| Published | May 19, 2026 |
| Last Updated | May 19, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None
Affected Versions
hestiacp / hestiacp
1.2.0 ≤ 1.9.4
References
mercuryiss.com.au: https://mercuryiss.com.au/hestiacp-unauthenticated-rce-ip-spoofing-cve-2026-43633-cve-2026-43634 github.com: https://github.com/hestiacp/hestiacp/issues/5229 github.com: https://github.com/hestiacp/hestiacp/pull/5273 github.com: https://github.com/hestiacp/hestiacp/commit/f381e294500f671cf12716c638afd0bfde901f88 vulncheck.com: https://www.vulncheck.com/advisories/hestiacp-ip-spoofing-via-cf-connecting-ip-header
Credits
sutol divinity76