CVE-2026-5625: GPT-Researcher XSS Vulnerability

CVE-2026-5625 Overview

A Cross-Site Scripting (XSS) vulnerability has been identified in assafelovic GPT-Researcher versions up to 3.4.3. This vulnerability affects the WebSocket Interface component, specifically within the file gpt_researcher/skills/researcher.py. By manipulating the task argument, an attacker can inject malicious scripts that execute in the context of a victim's browser session.

Critical Impact

Remote attackers can exploit this XSS vulnerability to execute arbitrary JavaScript in the browsers of users interacting with the GPT-Researcher WebSocket Interface, potentially leading to session hijacking, credential theft, or unauthorized actions on behalf of victims.

Affected Products

• assafelovic GPT-Researcher versions up to and including 3.4.3
• Applications utilizing the GPT-Researcher WebSocket Interface
• Systems exposing the researcher.py component to untrusted input

Discovery Timeline

• 2026-04-06 - CVE-2026-5625 published to NVD
• 2026-04-07 - Last updated in NVD database

Technical Details for CVE-2026-5625

Vulnerability Analysis

This vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting. The flaw resides in the gpt_researcher/skills/researcher.py file within the WebSocket Interface component. The vulnerability allows attackers to inject malicious script content through the task parameter, which is not properly sanitized before being rendered or processed by the application.

The exploit has been publicly disclosed and documented in GitHub Issue #1692, making this vulnerability known to potential attackers. The project maintainers were notified through an issue report but have not yet responded with a fix.

Root Cause

The root cause of this vulnerability is insufficient input validation and output encoding in the WebSocket Interface handler. When user-supplied data is passed through the task argument, the application fails to properly sanitize or encode the input before it is processed and reflected back to users. This allows specially crafted input containing JavaScript code to be executed in the context of other users' browser sessions.

Attack Vector

The attack can be launched remotely over the network and requires user interaction, where a victim must interact with a malicious payload delivered through the WebSocket Interface. An attacker can craft a malicious task parameter containing JavaScript code and deliver it to victims through various means such as phishing links or by exploiting the WebSocket communication channel.

The vulnerability manifests when untrusted input flows from the task argument through the researcher.py processing logic without proper sanitization. When this data is subsequently rendered in a user's browser, the malicious script executes with the same privileges as the legitimate application. For detailed technical analysis, see the VulDB entry #355415 and the GitHub issue report.

Detection Methods for CVE-2026-5625

Indicators of Compromise

• Unexpected JavaScript execution within GPT-Researcher WebSocket responses
• Unusual task parameter values containing <script> tags, event handlers, or encoded JavaScript
• Suspicious outbound connections from user browsers to unknown external domains after interacting with the application
• Evidence of session token exfiltration or unauthorized API calls

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect common XSS patterns in WebSocket traffic
• Monitor application logs for task parameter values containing HTML tags, JavaScript keywords, or encoding patterns (e.g., %3Cscript%3E)
• Deploy browser-based XSS detection mechanisms such as Content Security Policy (CSP) violation reporting
• Utilize endpoint detection and response (EDR) solutions to identify post-exploitation behaviors

Monitoring Recommendations

• Enable verbose logging for the WebSocket Interface to capture all incoming task parameter values
• Configure alerts for requests containing suspicious characters or patterns in user-controllable inputs
• Monitor for anomalous user behavior patterns that may indicate successful XSS exploitation
• Review CSP violation reports for indicators of attempted script injection

How to Mitigate CVE-2026-5625

Immediate Actions Required

• Restrict access to the GPT-Researcher WebSocket Interface to trusted users only until a patch is available
• Implement strict Content Security Policy (CSP) headers to mitigate the impact of successful XSS attacks
• Deploy input validation at the application boundary to filter known malicious patterns from the task parameter
• Consider temporarily disabling the affected WebSocket functionality if not critical to operations

Patch Information

As of the last update on 2026-04-07, no official patch has been released by the project maintainers. The vulnerability was reported through GitHub Issue #1692, but the project has not yet responded. Users should monitor the GPT-Researcher GitHub repository for security updates and upgrade to a patched version as soon as one becomes available.

Workarounds

• Implement server-side input sanitization to strip or encode HTML and JavaScript from the task parameter before processing
• Deploy a reverse proxy or WAF with XSS filtering rules in front of the GPT-Researcher application
• Apply the principle of least privilege by restricting WebSocket Interface access to authenticated and authorized users only
• Use output encoding libraries appropriate to your rendering context to ensure user-supplied data is safely displayed

# Example Content Security Policy header configuration (nginx)
add_header Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; connect-src 'self' wss://your-domain.com; frame-ancestors 'none';" always;

# Example input sanitization at nginx level (basic pattern blocking)
# Add to location block handling WebSocket connections
if ($arg_task ~* "<script|javascript:|on\w+=") {
    return 403;
}