CVE-2025-34128 is a high-severity buffer overflow vulnerability identified in the X360 VideoPlayer ActiveX control (VideoPlayer.ocx) version 2.6, developed by X360Soft. The vulnerability arises from improper handling of input size in the ConvertFile() method, where the control fails to check the length of input arguments before copying them into a buffer. This classic buffer overflow (CWE-120) can lead to memory corruption, allowing an attacker to execute arbitrary code within the context of the current process. Exploitation requires no privileges and no authentication, but does require user interaction, such as visiting a malicious web page or opening a crafted file that triggers the vulnerable ActiveX control. The vulnerability is rated with a CVSS 4.0 score of 8.6 (high), reflecting its network attack vector, low attack complexity, no privileges required, but requiring user interaction and resulting in high confidentiality, integrity, and availability impacts. Although no known exploits are currently reported in the wild, the lack of available patches increases the risk of future exploitation. ActiveX controls are primarily used in legacy Windows environments, often embedded in Internet Explorer or legacy applications, which remain in use in some enterprise and industrial settings. The vulnerability also relates to CWE-94 (Improper Control of Generation of Code), indicating potential for code injection or execution. Given the nature of ActiveX controls and their integration with Windows systems, exploitation could lead to full system compromise, data theft, or disruption of services.

For European organizations, this vulnerability poses significant risks, especially for those relying on legacy Windows environments or applications embedding the X360 VideoPlayer ActiveX control. Successful exploitation could lead to unauthorized code execution, enabling attackers to steal sensitive data, install malware, or disrupt business operations. Sectors such as manufacturing, healthcare, and government agencies that may still use legacy software with ActiveX components are particularly vulnerable. The high confidentiality impact could result in exposure of personal data protected under GDPR, leading to regulatory penalties and reputational damage. Integrity and availability impacts could disrupt critical services or workflows, causing operational downtime and financial losses. The requirement for user interaction means that phishing or social engineering campaigns could be effective attack vectors, increasing the threat surface. Additionally, the absence of patches means organizations must rely on mitigations or workarounds, which may not fully eliminate risk. The vulnerability’s exploitation could also be leveraged in targeted attacks or supply chain compromises within Europe.

Given the absence of official patches, European organizations should implement multiple layers of defense. First, identify and inventory all instances of X360 VideoPlayer ActiveX control version 2.6 within their environments, prioritizing removal or disabling of the control where possible. If removal is not feasible, restrict usage to trusted sites only by configuring Internet Explorer or legacy browsers’ security zones to high and disabling ActiveX controls from running on untrusted sites. Employ application whitelisting to prevent unauthorized execution of the vulnerable control. Use endpoint detection and response (EDR) tools to monitor for unusual behavior indicative of exploitation attempts, such as memory corruption or unexpected process activity. Educate users about the risks of interacting with untrusted content, emphasizing caution with email attachments and links. Network segmentation can limit exposure by isolating legacy systems from critical infrastructure. Additionally, consider deploying intrusion prevention systems (IPS) with signatures targeting known exploitation patterns once available. Finally, maintain up-to-date backups and incident response plans to quickly recover from potential compromises.