High 7.5Published May 19, 2026

CVE-2026-43634HestiaCP 1.2.0-1.9.4 IP Spoofing via CF-Connecting-IP Header

Updated under an hour ago (Oct 27, 2026, 1:30 AM ET)

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Exploited in the last 30 days

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.

CVSS: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness (CWE): CWE-348
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: VulnCheck
NVD analysis: Deferred
Record last updated: Jul 14, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

hestiacp hestiacp hestiacp:hestiacp (from the name)	from 1.2.0 through 1.9.4; f381e294500f671cf12716c638afd0bfde901f88 not affected	CNA record

References

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
https://github.com/hestiacp/hestiacp/commit/f381e294500f671cf12716c638afd0bfde901f88	patch
https://www.vulncheck.com/advisories/hestiacp-ip-spoofing-via-cf-connecting-ip-header	third-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.