CVE-2021-4226
RSFirewall < 1.1.25 - IP Block Bypass
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
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.
- Record
CVE-2021-4226- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-345
- Updated
- 2026-11-02
CVE List
RSFirewall < 1.1.25 - IP Block Bypass
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.
- Record
CVE-2021-4226- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-345
- Updated
- 2026-11-02
EUVDEUVD-2021-34084
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.
- Record
EUVD-2021-34084- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-j8wj-77mv-262g
RSFirewall tries to identify the original IP address by looking at different HTTP headers. A...
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.
- Record
GHSA-j8wj-77mv-262g- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-345, CWE-639
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-4226 is a critical vulnerability (CVSS 9.8) in Rsjoomla Rsfirewall\!, published December 15, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.55%, the 45th percentile. No source names a fixed version.