# Defender Security <= 6.4.0 - Unauthenticated IP Address Spoofing via Smart IP Detection

- **ID:** WPSEC-2026-2784
- **Plugin:** Defender Security – Malware Scanner, Login Security & Firewall (`defender-security`), https://wordpress.org/plugins/defender-security/
- **Affected versions:** from 4.9.0 before 6.4.1
- **Fixed in:** 6.4.1 (Update to 6.4.1 or later.)
- **Severity:** Low 3.7 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N)
- **Weakness:** CWE-348
- **Usage among sites WPSec scans:** plugin Low, affected versions Low (as of 2026-11-10)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/defender-security
- **Fix released:** 2026-11-09
- **Published:** 2026-11-10
- **URL:** https://wpsec.com/vuln/WPSEC-2026-2784/

## Description

The Defender Security plugin for WordPress is vulnerable to IP Address Spoofing via Smart IP Detection in versions 4.9.0 up to, and including, 6.4.0, due to the plugin reading the client IP from the saved detection header, X-Forwarded-For and X-Real-IP without verifying that the request came through a trusted proxy, and using the first public IP address found in them. This makes it possible for unauthenticated attackers to spoof their IP address on sites using automatic IP detection where those headers are not overwritten by a proxy (for example a Cloudflare-fronted site whose origin can be reached directly). They can then evade Login Lockout and IP bans, or match allowlisted IP addresses.

## References

- https://wpsec.com/vuln/WPSEC-2026-2784/
- https://plugins.svn.wordpress.org/defender-security/tags/6.4.1/
- https://wordpress.org/plugins/defender-security/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-2784/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Free to use, share and adapt, also commercially, if you credit WPSec and link to this advisory.