CVE-2026-57403 in GD Security Headers Plugin
Summary
by MITRE • 07/13/2026
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Milan Petrovic GD Security Headers gd-security-headers allows Reflected XSS.This issue affects GD Security Headers: from n/a through <= 1.8.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 07/13/2026
This cross-site scripting vulnerability resides within the GD Security Headers plugin for WordPress, specifically impacting versions up to and including 1.8. The flaw manifests as improper neutralization of input during web page generation, creating a reflected XSS attack vector that allows malicious actors to inject client-side scripts into web pages viewed by other users. The vulnerability stems from insufficient sanitization of user-supplied input parameters that are directly incorporated into dynamically generated HTML content without proper encoding or validation mechanisms.
The technical implementation of this vulnerability occurs when the plugin processes HTTP headers and incorporates user-provided data into response headers or page content without adequate input filtering. Attackers can craft malicious URLs containing script payloads that get reflected back to users browsing the affected WordPress site, enabling session hijacking, credential theft, or redirection to malicious sites. This weakness directly maps to CWE-79, which categorizes cross-site scripting vulnerabilities as improper neutralization of input during web page generation, and aligns with ATT&CK technique T1531 focusing on use of remote services for command and control.
The operational impact of this reflected XSS vulnerability extends beyond simple script injection, potentially allowing attackers to escalate privileges within the targeted WordPress environment. Once executed, malicious scripts can steal cookies, session tokens, or manipulate page content to redirect users to phishing sites. The vulnerability is particularly concerning in WordPress environments where administrators frequently interact with plugin settings and may inadvertently trigger the malicious payloads through dashboard navigation or administrative functions.
Mitigation strategies should prioritize immediate patching to versions beyond 1.8 where the XSS vulnerability has been addressed. Administrators must implement Content Security Policy headers to limit script execution sources and deploy proper input validation at all entry points. Additionally, regular security audits of WordPress plugins should include verification of input sanitization practices and monitoring for unusual header modifications that might indicate exploitation attempts. Network-level protections such as web application firewalls can provide additional defense-in-depth measures against known XSS patterns while implementing principle of least privilege access controls for plugin management functions.