CVE-2026-6617: Langgenius Dify SSRF Vulnerability

CVE-2026-6617 Overview

A Server-Side Request Forgery (SSRF) vulnerability has been identified in LangGenius Dify, an open-source platform for building AI-powered applications. The vulnerability exists in the get_api_tool_provider_remote_schema function within the api/services/tools/api_tools_manage_service.py file of the ApiToolManageService component. By manipulating the url argument, an attacker can force the server to make arbitrary HTTP requests to internal or external resources, potentially exposing sensitive internal services, cloud metadata endpoints, or enabling further attacks against internal infrastructure.

Critical Impact

Authenticated attackers can exploit this SSRF vulnerability to access internal network resources, probe internal services, and potentially exfiltrate sensitive data from cloud metadata services or internal APIs not intended to be externally accessible.

Affected Products

• LangGenius Dify versions up to and including 0.6.9
• ApiToolManageService component
• api/services/tools/api_tools_manage_service.py module

Discovery Timeline

• April 20, 2026 - CVE-2026-6617 published to NVD
• April 22, 2026 - Last updated in NVD database

Technical Details for CVE-2026-6617

Vulnerability Analysis

This vulnerability is classified as CWE-918: Server-Side Request Forgery (SSRF). The flaw resides in the get_api_tool_provider_remote_schema function, which processes user-supplied URL input without adequate validation or sanitization. When the application fetches the remote schema, it blindly trusts the provided URL parameter, allowing attackers to redirect requests to arbitrary destinations.

The exploit has been publicly disclosed through a GitHub Gist PoC Script, meaning attackers have access to working proof-of-concept code. The vendor was contacted regarding this disclosure but did not respond, leaving users without official guidance during the disclosure period.

Root Cause

The root cause of this vulnerability is insufficient input validation on the url parameter within the get_api_tool_provider_remote_schema function. The application fails to implement proper URL allowlisting, schema validation, or IP address blocking that would prevent requests to internal network ranges, localhost, or cloud metadata endpoints. This allows authenticated users to craft malicious URL values that redirect server-side HTTP requests to unintended targets.

Attack Vector

The attack is network-based and requires low-level authentication to the Dify platform. An authenticated attacker can exploit this vulnerability by submitting a crafted URL value to the vulnerable endpoint. The server then makes an HTTP request to the attacker-specified destination, potentially allowing:

• Access to internal services (databases, admin panels, internal APIs)
• Cloud metadata service access (e.g., AWS IMDSv1 at http://169.254.169.254/)
• Port scanning of internal network infrastructure
• Bypassing firewall restrictions to access protected resources
• Data exfiltration through DNS or HTTP channels

The vulnerability is exploited by manipulating the URL parameter in API requests to the ApiToolManageService endpoint. Attackers can supply internal IP addresses, localhost references, or cloud metadata URLs to probe internal infrastructure and potentially extract sensitive credentials or configuration data. Detailed exploitation techniques are available in the VulDB entry.

Detection Methods for CVE-2026-6617

Indicators of Compromise

• Unusual outbound HTTP requests from the Dify application server to internal IP ranges (10.x.x.x, 172.16.x.x, 192.168.x.x)
• Requests targeting cloud metadata endpoints (169.254.169.254, 169.254.170.2)
• High volume of requests to the api_tools_manage_service endpoint with varying URL parameters
• Server-side requests to localhost or loopback addresses (127.0.0.1, ::1)

Detection Strategies

• Implement network monitoring to detect anomalous outbound connections from the Dify application server
• Monitor application logs for requests to get_api_tool_provider_remote_schema with suspicious URL patterns
• Deploy web application firewall (WAF) rules to block SSRF attack patterns in URL parameters
• Configure egress filtering alerts for connections to private IP ranges from application servers

Monitoring Recommendations

• Enable verbose logging for the ApiToolManageService component to capture all URL parameter values
• Set up alerting for any requests to RFC 1918 private address ranges from the application tier
• Monitor DNS queries from the application server for unusual internal hostname resolution attempts
• Implement network segmentation monitoring to detect lateral movement attempts

How to Mitigate CVE-2026-6617

Immediate Actions Required

• Upgrade LangGenius Dify to a version newer than 0.6.9 when a patched release becomes available
• Implement network-level egress filtering to block requests from the application server to internal IP ranges
• Deploy a WAF with SSRF protection capabilities in front of the Dify application
• Review application logs for evidence of exploitation attempts

Patch Information

At the time of publication, no official patch has been released by the vendor. The vendor was contacted during the responsible disclosure process but did not respond. Organizations should monitor the LangGenius Dify GitHub repository for security updates and patch releases. Additional vulnerability details are available through the VulDB Submission #792231.

Workarounds

• Implement a reverse proxy or WAF rule to validate and sanitize URL parameters before they reach the application
• Configure network-level controls to prevent the Dify application server from making requests to internal network ranges
• Restrict access to the affected ApiToolManageService endpoint to trusted administrators only
• Deploy IP allowlisting at the network level to limit which external URLs the application can fetch

# Example iptables rules to block SSRF to internal networks
# Block requests to private IP ranges from application server
iptables -A OUTPUT -d 10.0.0.0/8 -m owner --uid-owner www-data -j DROP
iptables -A OUTPUT -d 172.16.0.0/12 -m owner --uid-owner www-data -j DROP
iptables -A OUTPUT -d 192.168.0.0/16 -m owner --uid-owner www-data -j DROP
iptables -A OUTPUT -d 169.254.169.254/32 -m owner --uid-owner www-data -j DROP