CVE-2021-47769: Bdtask Isshue XSS Vulnerability

CVE-2021-47769 Overview

CVE-2021-47769 is a persistent cross-site scripting (XSS) vulnerability affecting Bdtask Isshue Shopping Cart version 3.5. The vulnerability exists in title input fields across multiple modules including stock, customer, and invoice management. Attackers with privileged user accounts can inject malicious scripts that execute when victims preview the affected content, potentially enabling session hijacking, credential theft, and persistent phishing attacks within the application context.

Critical Impact

Authenticated attackers can achieve persistent script execution across stock, customer, and invoice modules, enabling session hijacking and phishing attacks against other users of the e-commerce platform.

Affected Products

• Bdtask Isshue Shopping Cart version 3.5
• Multi-Store E-commerce Shopping Cart Software by BDTask

Discovery Timeline

• 2026-01-15 - CVE CVE-2021-47769 published to NVD
• 2026-01-21 - Last updated in NVD database

Technical Details for CVE-2021-47769

Vulnerability Analysis

This persistent XSS vulnerability (CWE-79) stems from improper input sanitization in the Bdtask Isshue e-commerce platform. The application fails to adequately validate and sanitize user-supplied input in title fields across critical business modules. When privileged users enter data into these fields, the input is stored in the database without proper encoding or filtering. Subsequently, when other users or administrators preview or access records containing the malicious payload, the injected scripts execute in the context of their browser session.

The attack requires an authenticated user with access to create or modify records in the stock management, customer management, or invoice modules. Once the malicious script is stored, it persists in the application database and triggers each time the affected content is rendered, making this a stored/persistent XSS rather than a reflected variant.

Root Cause

The root cause of this vulnerability is insufficient input validation and output encoding in the title input fields of the Isshue Shopping Cart application. The application accepts arbitrary HTML and JavaScript content without proper sanitization when processing title fields in the stock, customer, and invoice modules. Additionally, the application fails to implement context-aware output encoding when rendering these stored values, allowing injected scripts to execute in victims' browsers.

Attack Vector

The attack is network-based and requires the attacker to have a privileged user account within the Isshue Shopping Cart application. The exploitation workflow involves:

1. An authenticated attacker accesses one of the vulnerable modules (stock, customer, or invoice management)
2. The attacker crafts a malicious payload containing JavaScript code and injects it into a title input field
3. The malicious content is stored in the application database without proper sanitization
4. When another user (typically an administrator or staff member) previews or views the affected record, the injected script executes in their browser
5. The attacker can then harvest session tokens, perform actions on behalf of the victim, or redirect them to phishing pages

This attack requires user interaction (victim must view the poisoned content) but the persistent nature means the payload remains active until the malicious content is identified and removed. Technical details and proof-of-concept information can be found in the Exploit-DB #50490 and Vulnerability Lab #2284 references.

Detection Methods for CVE-2021-47769

Indicators of Compromise

• Presence of encoded or obfuscated JavaScript in database fields for stock, customer, or invoice title entries
• Unusual <script>, <img onerror=, or event handler patterns in title fields
• Browser console errors or unexpected network requests when viewing stock, customer, or invoice records
• Reports of unexpected redirects or pop-ups from users accessing the application

Detection Strategies

• Implement web application firewall (WAF) rules to detect common XSS payloads in HTTP POST requests to stock, customer, and invoice endpoints
• Deploy database query logging to identify insertions of HTML/JavaScript patterns in title columns
• Enable Content Security Policy (CSP) violation reporting to detect script execution from unexpected sources
• Configure SentinelOne Singularity XDR to monitor for anomalous browser behavior patterns indicative of XSS exploitation

Monitoring Recommendations

• Monitor HTTP request logs for suspicious payload patterns such as <script>, javascript:, or HTML event handlers in POST data
• Implement database integrity monitoring to detect unexpected modifications to title fields containing script-like content
• Review access logs for unusual access patterns to stock, customer, and invoice preview functionality
• Enable alerting on CSP violations that may indicate attempted XSS exploitation

How to Mitigate CVE-2021-47769

Immediate Actions Required

• Audit all existing records in stock, customer, and invoice modules for potentially malicious content and sanitize or remove suspicious entries
• Implement strict input validation to reject HTML and JavaScript content in title fields
• Deploy output encoding for all user-supplied content rendered in the application
• Restrict access to vulnerable modules to trusted users only until patches are applied
• Implement Content Security Policy headers to mitigate the impact of any successful XSS exploitation

Patch Information

No vendor patch information is currently available for CVE-2021-47769. Organizations using Bdtask Isshue Shopping Cart version 3.5 should contact BDTask directly to inquire about security updates or consider upgrading to a newer version if available. Monitor the vendor's official channels for security advisories.

Workarounds

• Implement server-side input validation to strip or reject HTML tags and JavaScript from all title input fields
• Apply output encoding using context-appropriate encoding functions when rendering title fields in the application
• Deploy a Web Application Firewall (WAF) with XSS protection rules in front of the application
• Implement strict Content Security Policy (CSP) headers to prevent inline script execution: Content-Security-Policy: default-src 'self'; script-src 'self'
• Conduct regular security audits of database content to identify and remove any stored malicious payloads

# Example CSP header configuration for Apache
# Add to .htaccess or Apache configuration
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; frame-ancestors 'none';"

# Example CSP header for Nginx
# Add to server block
add_header Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; frame-ancestors 'none';";