CVE-2026-64624 – FreeRDP RDP File Parser Remote Code Execution via CLI Options

This vulnerability allows unauthenticated remote attackers to execute arbitrary code on servers hosting applications built with the AcmeWeb Framework. The flaw specifically resides within the templating engine's processing of user-supplied input. When an application renders user-controlled data directly into a template without proper context-aware sanitization or escaping, a specially crafted input string containing malicious template directives or expressions can bypass security controls. This can lead to the execution of arbitrary commands on the underlying operating system with the privileges of the web application process. Successful exploitation can result in full system compromise, data exfiltration, defacement, or further lateral movement within the compromised network segment.

1. IMMEDIATE ACTIONS

Immediately assess all systems utilizing the AcmeWeb Framework to identify potential exposure.
If feasible and business-critical operations allow, temporarily disconnect or isolate affected application instances from public internet access.
Implement emergency Web Application Firewall (WAF) rules to block known or suspected exploit patterns associated with template injection, such as common command execution syntax (e.g., process calls, file system access functions) within template expressions.
Review application and system logs for any indicators of compromise (IOCs), including unusual process creation by the web server user, unexpected outbound network connections, or modifications to critical system files. Prioritize logs from the past 24-48 hours.
Initiate an internal incident response process, notifying relevant security and operations teams.
Prepare for rapid deployment of patches by identifying all affected systems and planning for maintenance windows.

2. PATCH AND UPDATE INFORMATION

The primary remediation is to apply the official security patch released by the AcmeWeb Framework maintainers.
Specific affected versions are AcmeWeb Framework 3.x prior to 3.5.1, and 4.x prior to 4.2.0.
The patched versions that resolve this vulnerability are AcmeWeb Framework 3.5.1 and 4.2.0, or later releases.
Download patches directly from the official AcmeWeb Framework repository or vendor portal.
Thoroughly test all patches in a non-production staging environment that mirrors your production setup before deploying to production. Verify application functionality and performance post-patch.
Ensure all dependencies of the AcmeWeb Framework are also updated to their latest stable and secure versions, as the vulnerability might be exacerbated or influenced by outdated libraries.

3. MITIGATION STRATEGIES

Implement robust server-side input validation and sanitization for all user-supplied data, especially any data that will be rendered by the templating engine. Do not rely solely on client-side validation.
Ensure all output rendered by the templating engine is contextually escaped. Specifically, use the templating engine's built-in context-aware escaping functions (e.g., HTML escaping, URL escaping) for all user-controlled data to prevent the interpretation of malicious template directives. Avoid direct concatenation of user input into templates.
Run the web application process with the principle of least privilege. Restrict the operating system user account running the AcmeWeb Framework application to the minimum necessary permissions, preventing it from executing arbitrary system commands or accessing sensitive files outside its scope.
Implement network segmentation to isolate web application servers from sensitive internal networks and critical backend systems. This limits the potential blast radius if an RCE occurs.
Configure Web Application Firewalls (WAFs) with advanced rulesets to detect and block common template injection payloads, including unusual characters, function calls, or system commands within request parameters, headers, or body.
If not strictly required for application functionality, disable dangerous or powerful features within the templating engine that could facilitate RCE (e.g., direct access to system objects, reflection capabilities). Consult the AcmeWeb Framework documentation for guidance on securing the templating engine.
Consider deploying Runtime Application Self-Protection (RASP) solutions that can monitor application execution in real-time and block malicious behavior, such as unauthorized process creation or file