Is CVE-2021-4226 actively exploited?

No active exploitation of CVE-2021-4226 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-4226 be exploited remotely?

Yes. CVE-2021-4226 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-4226?

CVE-2021-4226 has a CVSS score of 9.8 (CRITICAL).

HOME VULNERABILITIESCVE-2021-4226

CRITICAL

CVE-2021-4226

NVD-CWE-noinfoPublished: December 15, 2022· Updated: Jun 17, 2026

9.8

CVSS v3.1

Official Description

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.

NVD Source

Risk Analysis

RSFirewall for Joomla contains a flaw in how it identifies original IP addresses via HTTP headers, leading to a security bypass. This critical vulnerability allows remote attackers to circumvent security controls.

No public exploit is known, and the vulnerability is not in the KEV catalog. It is remotely exploitable with low complexity.

Recommended Action

Update RSFirewall to the latest version to ensure correct IP header validation.

Generated by the CTIWATCH analysis pipeline from this CVE's metadata (CVSS, EPSS, KEV status, exploit intelligence). Verify against vendor advisories before acting.

Technical Analysis

CVE-2021-4226 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.