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
- Versión: 4.0
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- Puntuación base: 8.7
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.36%
- Percentil entre todas las CVEs puntuadas: 28
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1190Exploit Public-Facing Applicationinitial access95 % - Impacto principal
T1078Valid Accountsstealth · persistence · privilege escalation · initial access90 % - Impacto secundario
T1556Modify Authentication Processdefense impairment · persistence · credential access70 % - Impacto secundario
T1565.001Stored Data Manipulationimpact75 %
Vulnerabilidad de suplantación de IP en headers HTTP permite bypass de autenticación (T1078) sin credenciales válidas mediante falsificación de direcciones IP confiables (Cloudflare). Poisoning de logs de auditoría (T1565.001) y evasión de controles de autenticación (T1356 via T1078 + T1556) por acc
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
CWE
- CWE-348
Referencias
- 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
JSON original (NVD)
Mostrar
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"valueDensity": "NOT_DEFINED",
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"modifiedAttackRequirements": "NOT_DEFINED",
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"modifiedVulnIntegrityImpact": "NOT_DEFINED",
"vulnerabilityResponseEffort": "NOT_DEFINED",
"modifiedSubAvailabilityImpact": "NOT_DEFINED",
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"modifiedVulnConfidentialityImpact": "NOT_DEFINED"
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"affected": [
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"affectedData": [
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"descriptions": [
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"value": "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."
},
{
"lang": "es",
"value": "Las versiones de HestiaCP 1.2.0 a 1.9.4 contienen una vulnerabilidad de suplantación de IP que permite a atacantes remotos no autenticados eludir los controles de seguridad de autenticación al proporcionar una dirección IP arbitraria en el encabezado HTTP CF-Connecting-IP sin verificar que la solicitud se originó en la red de Cloudflare. Los atacantes pueden explotar esto para eludir la protección contra fuerza bruta de fail2ban, eludir las listas de permitidos de IP por usuario, y envenenar los registros de auditoría de autenticación al suplantar direcciones IP confiables en cada solicitud."
}
],
"lastModified": "2026-07-24T12:10:00.210",
"sourceIdentifier": "disclosure@vulncheck.com"
}