CVE-2026-43634

HestiaCP 1.2.0-1.9.4 IP Spoofing via CF-Connecting-IP Header

HIGH
7.5
CVSS Score
Published: May 19, 2026 at 01:33 PM UTC
Updated: July 24, 2026 at 12:23 PM UTC
1 product affected across 1 vendorHestiacp

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Severity
HIGH7.5
Exploit prediction
EPSS 0.2%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

1.2.0 ≤ v ≤ 1.9.41.2.0
Vendor states this is fixed in f381e294500f671cf12716c638afd0bfde901f88 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-348

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