CVE-2026-5623: Huly Platform SSRF Vulnerability

CVE-2026-5623 Overview

A Server-Side Request Forgery (SSRF) vulnerability has been identified in hcengineering Huly Platform version 0.7.382. The vulnerability exists in the Import Endpoint component, specifically within the file server/front/src/index.ts. This flaw allows attackers to manipulate server-side requests, potentially enabling access to internal resources, network scanning, or data exfiltration from behind firewalls.

Critical Impact

Remote attackers with low privileges can exploit this SSRF vulnerability to make the server perform arbitrary HTTP requests to internal or external resources, potentially exposing sensitive internal services and data.

Affected Products

• hcengineering Huly Platform version 0.7.382

Discovery Timeline

• 2026-04-06 - CVE CVE-2026-5623 published to NVD
• 2026-04-07 - Last updated in NVD database

Technical Details for CVE-2026-5623

Vulnerability Analysis

This vulnerability is classified as CWE-918 (Server-Side Request Forgery), a web security flaw that allows attackers to induce the server-side application to make HTTP requests to an arbitrary domain of the attacker's choosing. In the context of the Huly Platform, the Import Endpoint does not properly validate or sanitize user-supplied URLs before making server-side requests.

The exploitation requires network access and low-privilege authentication, making it accessible to any authenticated user of the platform. The exploit has been publicly disclosed, and the vendor (hcengineering) was contacted but did not respond to the disclosure.

Root Cause

The root cause of this vulnerability lies in insufficient input validation within the server/front/src/index.ts file. The Import Endpoint accepts user-controlled URL parameters without adequately verifying that the target destination is safe and authorized. This allows attackers to craft malicious import requests that redirect the server to make requests to internal network resources or external attacker-controlled servers.

Attack Vector

The attack is executed remotely over the network. An attacker with valid authentication credentials can submit a crafted request to the Import Endpoint containing a malicious URL. The server processes this request and makes an HTTP connection to the specified target, potentially:

1. Accessing internal services that should not be externally accessible
2. Scanning internal network infrastructure
3. Exfiltrating data through the server as a proxy
4. Interacting with cloud metadata services to steal credentials

The vulnerability manifests in the import functionality where user-supplied URLs are processed. Technical details are available through the VulDB vulnerability entry.

Detection Methods for CVE-2026-5623

Indicators of Compromise

• Unusual outbound HTTP requests from the Huly Platform server to internal IP ranges (e.g., 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16)
• Server requests to cloud metadata endpoints such as 169.254.169.254
• Unexpected connections to localhost or loopback addresses originating from the Import Endpoint
• High volume of import requests from a single authenticated user

Detection Strategies

• Implement network monitoring to detect server-initiated requests to internal IP ranges or restricted endpoints
• Review web application firewall (WAF) logs for suspicious URL patterns in import requests
• Monitor server logs for failed connection attempts to internal services
• Analyze import endpoint access patterns for anomalous behavior

Monitoring Recommendations

• Deploy egress filtering to restrict outbound connections from the Huly Platform server
• Enable detailed logging on the Import Endpoint to capture all URL parameters
• Set up alerts for any connections to private IP address ranges from the application server
• Monitor for unusual authentication patterns followed by import requests

How to Mitigate CVE-2026-5623

Immediate Actions Required

• Restrict access to the Import Endpoint to only trusted administrative users
• Implement network-level controls to block outbound requests to internal IP ranges from the Huly Platform server
• Consider temporarily disabling the import functionality until a patch is available
• Deploy a web application firewall with SSRF protection rules

Patch Information

At the time of publication, the vendor (hcengineering) has not responded to disclosure attempts and no official patch is available. Organizations should monitor the VulDB submission page for updates on remediation status. Consider reaching out to the vendor directly for patching timelines.

Workarounds

• Implement an allowlist of permitted domains for the Import Endpoint at the application or network level
• Use network segmentation to isolate the Huly Platform server from sensitive internal resources
• Deploy a forward proxy that validates and filters all outbound requests from the application server
• Disable the Import Endpoint entirely if the functionality is not critical to operations

# Example: Network-level mitigation using iptables to block internal network access
# Block requests to private IP ranges from the Huly Platform server
iptables -A OUTPUT -d 10.0.0.0/8 -j DROP
iptables -A OUTPUT -d 172.16.0.0/12 -j DROP
iptables -A OUTPUT -d 192.168.0.0/16 -j DROP
iptables -A OUTPUT -d 169.254.169.254 -j DROP