CVE-2025-6810: Mescius ActiveReports.NET RCE Vulnerability

CVE-2025-6810 Overview

CVE-2025-6810 is a critical insecure deserialization vulnerability affecting Mescius ActiveReports.NET. The vulnerability allows remote attackers to execute arbitrary code on affected installations through the improper handling of untrusted data in the ReadValue method. While interaction with the library is required to exploit this vulnerability, attack vectors may vary depending on the specific implementation.

The flaw stems from the lack of proper validation of user-supplied data, resulting in deserialization of untrusted data. An attacker can leverage this vulnerability to execute code in the context of the current process, potentially leading to complete system compromise.

Critical Impact

Remote attackers can achieve arbitrary code execution without authentication through malicious deserialization payloads, potentially compromising systems running applications that utilize the affected ActiveReports.NET library.

Affected Products

• Mescius ActiveReports.NET version 18.1.1
• Applications utilizing the affected ActiveReports.NET library
• .NET applications implementing ActiveReports reporting functionality

Discovery Timeline

• 2025-07-07 - CVE-2025-6810 published to NVD
• 2025-08-14 - Last updated in NVD database

Technical Details for CVE-2025-6810

Vulnerability Analysis

This vulnerability is classified as CWE-502 (Deserialization of Untrusted Data), a well-known class of security flaws that can lead to remote code execution. The vulnerability exists within the ReadValue method implementation in the ActiveReports.NET library.

When the ReadValue method processes serialized data, it fails to adequately validate the input before deserializing it. This allows an attacker to craft a malicious serialized object that, when processed by the vulnerable method, executes arbitrary code within the application's process context.

The network-accessible nature of this vulnerability, combined with the lack of authentication requirements and low attack complexity, makes it particularly dangerous for exposed systems. Successful exploitation can result in complete compromise of confidentiality, integrity, and availability of the affected system.

Root Cause

The root cause of CVE-2025-6810 is the absence of proper input validation and type checking in the ReadValue method before deserialization occurs. The method accepts user-controlled serialized data and processes it without verifying that the data originates from a trusted source or conforms to expected object types.

In .NET deserialization vulnerabilities, attackers can leverage gadget chains—sequences of existing classes within the application or framework that, when chained together during deserialization, result in arbitrary code execution.

Attack Vector

The attack vector for this vulnerability is network-based, requiring the attacker to deliver a malicious serialized payload to an application utilizing the vulnerable ActiveReports.NET library. The specific attack surface depends on how the library is implemented within the target application.

Common attack scenarios include:

• Applications that accept serialized report data from external sources
• Web applications that deserialize ActiveReports objects from user input
• Services that process report definitions or configurations from untrusted sources

The exploitation mechanism involves crafting a malicious serialized object containing a gadget chain that triggers code execution when the ReadValue method processes it. No user interaction is required beyond the application processing the malicious input, and no prior authentication is needed.

Detection Methods for CVE-2025-6810

Indicators of Compromise

• Unexpected process spawning from applications utilizing ActiveReports.NET
• Anomalous network connections originating from reporting application processes
• Suspicious file system modifications by processes handling report generation
• Unusual CPU or memory consumption during report processing operations

Detection Strategies

• Monitor for deserialization-related exceptions or errors in application logs related to ActiveReports components
• Implement application-level logging for all ReadValue method invocations
• Deploy endpoint detection to identify known .NET deserialization gadget chain patterns
• Scan for unexpected binary payloads in incoming report data streams

Monitoring Recommendations

• Enable verbose logging for ActiveReports.NET library operations
• Configure SIEM alerts for suspicious process behavior from applications using the affected library
• Monitor network traffic for unusual outbound connections from reporting services
• Implement file integrity monitoring on systems running vulnerable applications

How to Mitigate CVE-2025-6810

Immediate Actions Required

• Identify all applications and systems using Mescius ActiveReports.NET version 18.1.1
• Restrict network access to affected applications where possible
• Implement input validation and sanitization for any data processed by ActiveReports.NET
• Consider temporarily disabling functionality that processes external report data until patched

Patch Information

Organizations should consult the Zero Day Initiative Advisory ZDI-25-448 for detailed information about available patches and remediation guidance from the vendor.

Contact Mescius directly for official patch availability and updated versions of ActiveReports.NET that address this vulnerability. Prioritize patching given the critical severity and remote code execution impact.

Workarounds

• Implement strict input validation on all data processed by ActiveReports.NET before deserialization
• Use allowlist-based type filtering to restrict which object types can be deserialized
• Deploy network segmentation to isolate systems running vulnerable applications
• Consider implementing a Web Application Firewall (WAF) with rules to detect malicious serialized payloads

For environments where immediate patching is not possible, implement defense-in-depth measures including restricting which users and systems can interact with applications utilizing the vulnerable library, and enhancing monitoring for signs of exploitation attempts.