CVE-2026-31352: Feehi CMS Stored XSS Vulnerability

CVE-2026-31352 Overview

An authenticated stored cross-site scripting (XSS) vulnerability has been identified in Feehi CMS v2.1.1. The vulnerability exists within the Role Management module, where attackers with authenticated access can inject malicious web scripts or HTML content through the Role Name parameter. Once stored, the malicious payload executes whenever other users view the affected role entry, potentially leading to session hijacking, credential theft, or further compromise of the CMS administration panel.

Critical Impact

Authenticated attackers can persistently inject malicious scripts that execute in the context of other administrators' sessions, potentially leading to account takeover and administrative privilege abuse.

Affected Products

• Feehi CMS v2.1.1
• feehi:feehi_cms component

Discovery Timeline

• 2026-04-06 - CVE-2026-31352 published to NVD
• 2026-04-09 - Last updated in NVD database

Technical Details for CVE-2026-31352

Vulnerability Analysis

This stored cross-site scripting vulnerability (CWE-79) occurs due to insufficient input validation and output encoding in the Role Management module of Feehi CMS. The application fails to properly sanitize user-supplied input in the Role Name parameter before storing it in the database and subsequently rendering it in the administrative interface.

The attack requires authenticated access to the CMS, meaning the attacker must have at least basic administrative privileges to access the Role Management functionality. However, once the malicious payload is stored, it will execute in the browser context of any user who views the role configuration, including higher-privileged administrators. This "changed scope" characteristic means the vulnerability can impact users beyond the attacker's initial access level.

The vulnerability is network-accessible and requires minimal complexity to exploit, though user interaction is required for the payload to execute (the victim must view the page containing the stored XSS). The impact includes potential confidentiality breaches through session token theft and integrity violations through unauthorized actions performed via the victim's session.

Root Cause

The root cause of this vulnerability is improper input validation and missing output encoding in the Role Management module. The application accepts and stores arbitrary HTML and JavaScript content in the Role Name field without proper sanitization. When this data is rendered in the administrative interface, it is not properly encoded, allowing the injected script to execute in the victim's browser.

Attack Vector

The attack is conducted over the network by an authenticated user with access to the Role Management functionality. The attacker navigates to the role creation or editing interface and injects a crafted XSS payload into the Role Name parameter. Common payload examples include script tags containing JavaScript code designed to steal cookies, redirect users, or perform actions on behalf of the victim.

The vulnerability is a stored XSS, meaning the malicious content persists in the application's database. Each time an administrator accesses the Role Management section or views pages that display role names, the injected script executes automatically in their browser context. This persistence makes the attack particularly dangerous as it can affect multiple users over time without requiring repeated attacker interaction.

Detection Methods for CVE-2026-31352

Indicators of Compromise

• Unusual JavaScript content or HTML tags present in database fields for role names
• Role entries containing encoded script payloads such as <script>, onerror=, or onload= event handlers
• Unexpected outbound requests from administrator browsers to external domains
• Session token anomalies or unauthorized administrative actions in audit logs

Detection Strategies

• Implement web application firewall (WAF) rules to detect XSS patterns in POST requests to the Role Management endpoints
• Review database entries for role names containing suspicious HTML or JavaScript content
• Monitor administrative session activity for signs of session hijacking or unauthorized actions
• Deploy Content Security Policy (CSP) headers to detect and block inline script execution

Monitoring Recommendations

• Enable detailed logging for all Role Management module operations including create, update, and delete actions
• Configure alerting for any database modifications to role-related tables containing HTML entities or script tags
• Monitor network traffic from administrative workstations for unusual external connections
• Implement integrity monitoring for CMS configuration and role management data

How to Mitigate CVE-2026-31352

Immediate Actions Required

• Audit all existing role entries in the database for potentially malicious content and remove any suspicious payloads
• Restrict access to the Role Management module to only essential administrators until a patch is available
• Implement input validation at the application or WAF level to reject role names containing HTML or script content
• Deploy Content Security Policy (CSP) headers to mitigate the impact of any stored XSS payloads

Patch Information

At the time of publication, users should monitor the Feehi CMS GitHub repository for security updates. The vulnerability has been reported via GitHub Issue #83. Organizations using Feehi CMS v2.1.1 should upgrade to a patched version as soon as one becomes available.

Workarounds

• Implement server-side input validation to strip or reject HTML tags and JavaScript event handlers from the Role Name parameter
• Deploy a web application firewall with XSS detection rules for administrative endpoints
• Add output encoding to all locations where role names are displayed in the administrative interface
• Implement Content Security Policy headers with strict script-src directives to prevent inline script execution