NAXSI is an open-source maintenance web application firewall (WAF) for NGINX. An issue present starting in version 1.3 and prior to version 1.6 allows someone to bypass the WAF when a malicious `X-Forwarded-For` IP matches `IgnoreIP` `IgnoreCIDR` rules. This old code was arranged to allow older NGINX versions to also support `IgnoreIP` `IgnoreCIDR` when multiple reverse proxies were present. The issue is patched in version 1.6. As a workaround, do not set any `IgnoreIP` `IgnoreCIDR` for older versions.
https://github.com/wargio/naxsi/security/advisories/GHSA-7qjc-q4j9-pc8x
https://github.com/wargio/naxsi/pull/103
https://github.com/wargio/naxsi/commit/1b712526ed3314dd6be7e8b0259eabda63c19537