CVE-2026-43634

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 v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/hestiacp/hestiacp/commit/f381e294500f671cf12716c638afd0bfde901f88
https://github.com/hestiacp/hestiacp/issues/5229
https://github.com/hestiacp/hestiacp/pull/5273
https://mercuryiss.com.au/hestiacp-unauthenticated-rce-ip-spoofing-cve-2026-43633-cve-2026-43634
https://www.vulncheck.com/advisories/hestiacp-ip-spoofing-via-cf-connecting-ip-header

Configurations

No configuration.

History

19 May 2026, 15:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-05-19 15:16

Updated : 2026-05-19 17:57

NVD link : CVE-2026-43634

Mitre link : CVE-2026-43634

CVE.ORG link : CVE-2026-43634

JSON object : View

Products Affected

No product.

CWE

CWE-348

Use of Less Trusted Source

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