CVE-2026-40282: WeGIA Stored XSS Vulnerability

CVE-2026-40282 Overview

CVE-2026-40282 is a Stored Cross-Site Scripting (XSS) vulnerability affecting WeGIA, a web manager for charitable institutions. This vulnerability allows an authenticated user to inject malicious JavaScript into the Intercorrências notification page, which is executed when any user accesses the page, enabling session hijacking and account takeover.

Critical Impact

Authenticated attackers can inject persistent malicious scripts that execute in the context of other users' sessions, potentially leading to session hijacking, credential theft, and complete account takeover.

Affected Products

• WeGIA versions prior to 3.6.10

Discovery Timeline

• April 17, 2026 - CVE-2026-40282 published to NVD
• April 20, 2026 - Last updated in NVD database

Technical Details for CVE-2026-40282

Vulnerability Analysis

This Stored Cross-Site Scripting vulnerability exists in the WeGIA web manager's Intercorrências notification functionality. Unlike reflected XSS attacks where malicious scripts are immediately returned to the user, this stored variant persists the malicious payload within the application's data storage, causing it to execute every time a user views the affected notification page.

The vulnerability is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation), indicating that user-supplied input is not properly sanitized or encoded before being rendered in the browser context. An attacker with valid authentication credentials can craft malicious JavaScript payloads that become permanently embedded within the notification system.

Root Cause

The root cause is improper input validation and output encoding in the Intercorrências notification page. The application fails to sanitize user-controlled input before storing it and does not properly encode the content when rendering it back to users. This allows JavaScript code to be embedded directly into the HTML output, where it executes within the victim's browser session.

Attack Vector

The attack vector is network-based and requires user interaction. An authenticated attacker injects malicious JavaScript through the Intercorrências notification functionality. When other users, including administrators, access the affected notification page, the malicious script executes within their browser session.

The injected script can:

• Steal session cookies and authentication tokens
• Perform actions on behalf of the victim user
• Redirect users to phishing pages
• Capture keystrokes and form data
• Escalate privileges if an administrator views the page

The vulnerability mechanism involves the improper handling of user input in the notification storage and display functions. When a malicious payload such as an event handler or script tag is submitted through the notification interface, it is stored without sanitization. Subsequently, when any user navigates to the Intercorrências page, the stored payload is rendered directly into the HTML document and executed by the browser.

For complete technical details, see the GitHub Security Advisory.

Detection Methods for CVE-2026-40282

Indicators of Compromise

• Unexpected JavaScript execution or browser behavior when accessing the Intercorrências notification page
• Suspicious entries in notification data containing script tags, event handlers, or JavaScript URIs
• Anomalous session activity or unauthorized actions performed by legitimate user accounts
• Browser console errors indicating blocked inline scripts if Content Security Policy is enabled

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block XSS payloads in POST/PUT requests to notification endpoints
• Configure browser-based XSS detection headers and Content Security Policy to restrict inline script execution
• Deploy endpoint detection solutions to monitor for suspicious browser activity and unauthorized session token access
• Review application logs for unusual input patterns containing HTML tags, script elements, or event handlers

Monitoring Recommendations

• Enable detailed logging for all user input submitted to the notification functionality
• Monitor for outbound connections to unknown domains that could indicate data exfiltration
• Track session token usage patterns to identify potential session hijacking attempts
• Implement real-time alerting for detected XSS payloads in application input

How to Mitigate CVE-2026-40282

Immediate Actions Required

• Upgrade WeGIA to version 3.6.10 or later immediately
• Review existing notification data for suspicious JavaScript content and sanitize if necessary
• Implement Content Security Policy headers to mitigate the impact of any undetected XSS
• Force session token rotation for all users to invalidate potentially compromised sessions

Patch Information

The vulnerability has been fixed in WeGIA version 3.6.10. Organizations should upgrade to this version or later to address the stored XSS vulnerability. The security patch information is available in the GitHub Security Advisory GHSA-r6h8-7vxv-q8pp.

Workarounds

• Restrict access to the Intercorrências notification feature to trusted administrators only until patching is complete
• Deploy a web application firewall with XSS detection rules to filter malicious input
• Implement strict Content Security Policy headers to prevent inline script execution
• Review and sanitize existing notification entries to remove any potentially malicious content

# Example Content Security Policy header configuration
# Add to web server configuration to mitigate XSS impact

# Apache (.htaccess or httpd.conf)
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none';"

# Nginx (nginx.conf)
add_header Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none';";