CVE-2025-68924: Umbraco Forms RCE Vulnerability

CVE-2025-68924 Overview

CVE-2025-68924 is a Remote Code Execution (RCE) vulnerability affecting Umbraco UmbracoForms through version 8.13.16. An authenticated attacker can supply a malicious WSDL (Web Services Description Language) URL as a data source, enabling arbitrary code execution on the target server. This vulnerability falls under CWE-829 (Inclusion of Functionality from Untrusted Control Sphere), where the application improperly incorporates external resources without adequate validation.

Critical Impact

Authenticated attackers can achieve remote code execution by injecting malicious WSDL URLs, potentially leading to complete server compromise, data exfiltration, and lateral movement within the network.

Affected Products

• Umbraco Forms through version 8.13.16
• Umbraco CMS installations utilizing the UmbracoForms package
• Systems exposing Umbraco Forms web service data source functionality

Discovery Timeline

• 2026-01-16 - CVE-2025-68924 published to NVD
• 2026-01-16 - Last updated in NVD database

Technical Details for CVE-2025-68924

Vulnerability Analysis

The vulnerability exists in the Umbraco Forms package's handling of WSDL (Web Services Description Language) URLs when configured as data sources. The application processes external WSDL definitions without properly validating or sanitizing the remote resource, enabling Server-Side Request Forgery (SSRF) combined with code execution through malicious service definitions.

When an authenticated user with form configuration privileges supplies a WSDL URL, the application fetches and parses the remote service description. A malicious WSDL file can include references to external resources or exploit the XML parsing mechanism to achieve code execution through various means, including deserialization attacks or dynamic code generation based on the service contract.

Root Cause

The root cause is CWE-829: Inclusion of Functionality from Untrusted Control Sphere. The Umbraco Forms application trusts external WSDL URLs without implementing adequate security controls such as:

• URL allowlisting to restrict permitted external domains
• Content validation of the fetched WSDL document
• Sandboxed execution of dynamically generated proxy code
• Input sanitization for the WSDL URL parameter

This design flaw allows authenticated attackers to point the application at attacker-controlled infrastructure serving malicious WSDL content.

Attack Vector

The attack is network-based, requiring an authenticated session with privileges to configure form data sources. The attacker workflow involves:

1. Authenticating to the Umbraco backend with form configuration permissions
2. Navigating to form data source configuration
3. Providing a WSDL URL pointing to attacker-controlled infrastructure
4. The server fetches and processes the malicious WSDL
5. Code execution occurs during WSDL parsing or proxy generation

The attack does not require user interaction beyond the attacker's own authenticated session, though it requires low privileges (authenticated user) and involves high attack complexity due to the need for controlled infrastructure and crafted payloads.

Detection Methods for CVE-2025-68924

Indicators of Compromise

• Unusual outbound HTTP/HTTPS requests from web servers to external endpoints fetching WSDL files
• Form data source configurations containing external URLs not on corporate-approved lists
• Web server logs showing requests to unexpected external domains from the Umbraco application
• Presence of dynamically generated proxy classes or assemblies that were not part of the original deployment

Detection Strategies

• Monitor Umbraco Forms configuration changes, particularly data source URL modifications
• Implement egress filtering and log analysis for outbound connections from web servers
• Review audit logs for authenticated users modifying form configurations with external URLs
• Deploy web application firewall (WAF) rules to detect WSDL-related exploitation patterns

Monitoring Recommendations

• Enable detailed logging for Umbraco Forms configuration changes and data source access
• Configure alerts for outbound connections from web servers to non-allowlisted external hosts
• Monitor for process execution anomalies on servers hosting Umbraco installations
• Implement file integrity monitoring on Umbraco application directories to detect unauthorized changes

How to Mitigate CVE-2025-68924

Immediate Actions Required

• Upgrade Umbraco Forms to a patched version beyond 8.13.16 as soon as an update is available
• Review existing form configurations for suspicious external WSDL URLs
• Restrict network egress from Umbraco servers to only necessary external endpoints
• Audit user accounts with form configuration privileges and apply principle of least privilege

Patch Information

Organizations should monitor the GitHub Security Advisory for official patch information from Umbraco. The vulnerability affects UmbracoForms through version 8.13.16, and users should upgrade to the latest patched version when released. Package updates can be obtained via the NuGet Package for Umbraco Forms.

Workarounds

• Implement strict network egress controls to prevent the Umbraco server from making outbound connections to untrusted hosts
• Disable or restrict access to the WSDL/Webservice data source functionality if not required
• Apply Web Application Firewall rules to block external WSDL URL submissions in form configurations
• Limit form configuration privileges to only essential administrative accounts with strong authentication

# Example: Network egress restriction using iptables (Linux)
# Block outbound HTTP/HTTPS except to approved hosts
iptables -A OUTPUT -p tcp --dport 80 -d approved-host.example.com -j ACCEPT
iptables -A OUTPUT -p tcp --dport 443 -d approved-host.example.com -j ACCEPT
iptables -A OUTPUT -p tcp --dport 80 -j DROP
iptables -A OUTPUT -p tcp --dport 443 -j DROP