---
cve: "CVE-2021-4226"
severity: "CRITICAL"
cvss: 9.8
epss: "0.5%"
vendor: "Unknown"
kev: false
exploited: false
published: "2022-12-15 17:14:40"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-10-28T21:09:20+01:00"
---

# CVE-2021-4226

> 9.8 CRITICAL

## Beschreibung

RSFirewall tries to identify the original IP address by looking at different HTTP headers. A bypass is possible due to the way it is implemented.

## CNA-Record (Kanon, cvelistV5)

- CNA: **WPScan**
- State: PUBLISHED
- Stand: 2025-04-21 14:18:04

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **poc**
  - Automatable: **yes**
  - Technical Impact: **total**

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Schwachstellen-Klasse

- **CWE-345** — Insufficient Verification of Data Authenticity
  The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.

## Angriffsmuster (CAPEC)

- [CAPEC-111 — JSON Hijacking (aka JavaScript Hijacking)](https://capec.mitre.org/data/definitions/111.html) _(Severity: High)_
- [CAPEC-141 — Cache Poisoning](https://capec.mitre.org/data/definitions/141.html) _(Severity: High)_
- [CAPEC-142 — DNS Cache Poisoning](https://capec.mitre.org/data/definitions/142.html) _(Severity: High)_
- [CAPEC-148 — Content Spoofing](https://capec.mitre.org/data/definitions/148.html) _(Severity: Medium)_
- [CAPEC-218 — Spoofing of UDDI/ebXML Messages](https://capec.mitre.org/data/definitions/218.html) _(Severity: Medium)_
- [CAPEC-384 — Application API Message Manipulation via Man-in-the-Middle](https://capec.mitre.org/data/definitions/384.html) _(Severity: Low)_
- [CAPEC-385 — Transaction or Event Tampering via Application API Manipulation](https://capec.mitre.org/data/definitions/385.html) _(Severity: Medium)_
- [CAPEC-386 — Application API Navigation Remapping](https://capec.mitre.org/data/definitions/386.html) _(Severity: Medium)_

## ATT&CK-Techniken

- [T1557.002 — Adversary-in-the-Middle: ARP Cache Poisoning](https://attack.mitre.org/techniques/T1557/002/)
- [T1584.002 — Compromise Infrastructure: DNS Server](https://attack.mitre.org/techniques/T1584/002/)
- [T1491 — Defacement](https://attack.mitre.org/techniques/T1491/)

## Referenzen

- <https://wpscan.com/vulnerability/c0ed80c8-ebbf-4ed9-b02f-31660097c352>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2021-4226/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_