CVE-2026-5003: localGPT Information Disclosure Flaw

CVE-2026-5003 Overview

CVE-2026-5003 is an information disclosure vulnerability discovered in PromtEngineer localGPT, a locally-hosted AI assistant solution. The vulnerability exists within the handle_index function located in the rag_system/api_server.py file of the Web Interface component. An attacker can remotely manipulate requests to the affected function, resulting in unauthorized information disclosure. The exploit has been made public and could be leveraged in attacks targeting vulnerable instances.

Critical Impact

Remote attackers can exploit this vulnerability to access sensitive information without authentication, potentially exposing private data processed by the localGPT application.

Affected Products

• PromtEngineer localGPT up to commit 4d41c7d1713b16b216d8e062e51a5dd88b20b054
• localGPT Web Interface component
• RAG System API Server (rag_system/api_server.py)

Discovery Timeline

• 2026-03-28 - CVE-2026-5003 published to NVD
• 2026-03-30 - Last updated in NVD database

Technical Details for CVE-2026-5003

Vulnerability Analysis

This vulnerability falls under CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor). The flaw resides in how the handle_index function within the RAG (Retrieval-Augmented Generation) system's API server processes incoming requests. When exploited, the vulnerability allows an unauthorized remote attacker to extract sensitive information from the localGPT instance.

The localGPT project uses a rolling release model for continuous delivery, which means there are no discrete version numbers to track. The affected code is identified by the Git commit hash 4d41c7d1713b16b216d8e062e51a5dd88b20b054 and earlier.

The vendor (PromtEngineer) was contacted regarding this vulnerability but did not respond, leaving users without an official patch or guidance.

Root Cause

The root cause of this vulnerability is improper input validation and access control within the handle_index function of the API server. The function fails to properly sanitize or restrict access to certain requests, allowing attackers to manipulate parameters in a way that exposes internal information that should not be accessible to unauthenticated users.

Attack Vector

The attack is network-based and can be initiated remotely without requiring any user interaction or prior authentication. An attacker can craft malicious requests to the Web Interface component targeting the handle_index endpoint. By manipulating request parameters, the attacker can trigger the information disclosure condition, potentially revealing sensitive data such as configuration details, processed documents, or internal application state.

The vulnerability can be exploited over the network, making any internet-exposed localGPT instance a potential target. The public availability of the exploit increases the risk of widespread exploitation.

Detection Methods for CVE-2026-5003

Indicators of Compromise

• Unusual or malformed requests targeting the /index or related API endpoints in localGPT
• Unexpected data responses containing internal configuration or sensitive information
• Anomalous access patterns to the rag_system/api_server.py endpoints from unknown IP addresses
• Log entries showing repeated requests with manipulated parameters to the Web Interface

Detection Strategies

• Monitor web server access logs for suspicious requests to the localGPT API server, particularly the handle_index endpoint
• Implement web application firewall (WAF) rules to detect and block exploitation attempts targeting information disclosure patterns
• Review application logs for error messages or exceptions that may indicate exploitation attempts
• Deploy intrusion detection systems (IDS) with signatures for known localGPT exploitation patterns

Monitoring Recommendations

• Enable verbose logging for the localGPT Web Interface to capture detailed request information
• Set up alerting for unusual response sizes that may indicate data exfiltration
• Monitor network traffic for suspicious outbound connections from the localGPT server
• Regularly audit access to the localGPT instance and review authentication logs

How to Mitigate CVE-2026-5003

Immediate Actions Required

• Restrict network access to localGPT instances to trusted IP addresses only
• Implement authentication and authorization controls in front of the Web Interface
• Consider taking vulnerable localGPT instances offline until a fix is available
• Review access logs for any signs of previous exploitation

Patch Information

No official patch is currently available from the vendor. The PromtEngineer team was contacted about this vulnerability but did not respond. Users should monitor the GitHub Issue Discussion and the official localGPT repository for updates. Additional technical details are available in the VulDB Vulnerability Report.

Workarounds

• Place the localGPT Web Interface behind a reverse proxy with authentication requirements
• Implement IP allowlisting to restrict access to the API server to known, trusted sources
• Use network segmentation to isolate localGPT instances from untrusted networks
• Disable the Web Interface component if not required and use alternative access methods

# Configuration example - Restrict access using iptables
# Allow only trusted IP addresses to access localGPT port (default: 5110)
iptables -A INPUT -p tcp --dport 5110 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 5110 -j DROP

# Alternatively, use nginx as reverse proxy with basic auth
# /etc/nginx/sites-available/localgpt
# location /api/ {
#     auth_basic "Restricted Access";
#     auth_basic_user_file /etc/nginx/.htpasswd;
#     proxy_pass http://127.0.0.1:5110/;
# }