Executive Summary

CVE-2026-12488 is a memory corruption vulnerability found in the GV-Cloud functionality of GeoVision GV-VMS version 20.0.2. It is caused by a stack-based buffer overflow in the GvRelayProxy.dll file, which manages cloud-to-local communication for remote monitoring and operation of the VMS system.

The vulnerability occurs because the software does not properly validate the size of incoming messages, allowing an attacker to send oversized data that overflows a stack buffer of 4072 bytes.

Exploitation requires an attacker to impersonate the legitimate server, for example through a man-in-the-middle attack or DNS tampering, since the function responsible for connecting to the relay server does not verify the server's identity.

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Compliance Impact

The provided information does not explicitly describe how CVE-2026-12488 affects compliance with common standards and regulations such as GDPR or HIPAA.

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Impact Analysis

This vulnerability can lead to a denial of service (DoS) condition, disrupting the normal operation of the GeoVision GV-VMS system.

Additionally, under certain conditions such as disclosure of the stack cookie or favorable memory layout, it may allow remote code execution, which could enable an attacker to execute arbitrary code on the affected system.

Since exploitation requires impersonation of the legitimate server, an attacker could potentially intercept or manipulate network traffic to trigger the vulnerability.

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Detection Guidance

This vulnerability can be detected by monitoring network traffic for suspicious or specially crafted requests targeting the GV-Cloud functionality of GeoVision GV-VMS V20.0.2, particularly those attempting to connect to the relay server.

Since exploitation requires impersonation of the legitimate server, detection efforts should focus on identifying man-in-the-middle attacks or DNS tampering attempts that redirect traffic to malicious servers.

Commands to help detect this may include network traffic capture and analysis tools such as:

• Using tcpdump or Wireshark to capture and analyze traffic on the relevant ports used by GV-VMS for cloud communication.
• Example tcpdump command: tcpdump -i <interface> host <GV-VMS server IP> and port <relevant port>
• Checking DNS records and monitoring for unexpected changes or suspicious DNS responses that could indicate DNS tampering.
• Using tools like dig or nslookup to verify DNS integrity for the GV-VMS relay server domain.

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Mitigation Strategies

The immediate mitigation step is to apply the vendor's patch released on December 2, 2025, which fixes the stack-based buffer overflow in the GvRelayProxy.dll file.

Additional mitigation measures include:

• Ensuring that network communications to the GV-VMS relay server are secured and that server identity is properly verified to prevent impersonation attacks.
• Implementing network-level protections such as firewall rules to restrict access to the GV-VMS cloud communication ports only to trusted servers.
• Monitoring DNS configurations to prevent tampering that could redirect traffic to malicious servers.

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