What’s Vulnerable › Vulnerabilities

CVE-2021-4226: RSFirewall < 1.1.25 - IP Block Bypass

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2022-12-15 · updated 2026-06-17
• Weakness: CWE-345

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.

Affected products

• RSFirewall!: before 1.1.25 — fixed in 1.1.25

How to fix

Upgrade to a fixed version: RSFirewall! 1.1.25. Check the vendor advisory for mitigations.

References

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

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