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 arguments before copying them into a buffer. This classic buffer overflow (CWE-120) can lead to memory corruption, enabling an attacker to execute arbitrary code within the context of the current process. The vulnerability does not require any privileges or authentication but does require user interaction, such as visiting a malicious website or opening a crafted file that triggers the vulnerable ActiveX control. The CVSS 4.0 base score is 8.6, reflecting a high severity due to the network attack vector, low attack complexity, no privileges required, but user interaction needed, and high impact on confidentiality, integrity, and availability. The vulnerability is particularly dangerous because ActiveX controls run with the privileges of the hosting application, often Internet Explorer or legacy Windows applications, potentially allowing full system compromise if exploited. No patches or fixes have been published yet, and no known exploits are currently in the wild, though the vulnerability is publicly disclosed and could be targeted by attackers in the near future. The vulnerability also relates to CWE-94 (Improper Control of Generation of Code), indicating potential risks of code injection or execution beyond simple memory corruption. Given the widespread use of ActiveX controls in legacy enterprise environments, this vulnerability poses a significant risk to affected systems.

For European organizations, the impact of CVE-2025-34128 could be substantial, especially in sectors relying on legacy Windows environments and applications that embed ActiveX controls, such as government agencies, financial institutions, and industrial enterprises. Exploitation could lead to unauthorized code execution, data breaches, disruption of services, and potential lateral movement within networks. The vulnerability's ability to compromise confidentiality, integrity, and availability means sensitive data could be exfiltrated or corrupted, and critical systems could be taken offline or manipulated. Since the exploit requires user interaction, phishing or social engineering campaigns targeting European users could be effective attack vectors. Additionally, organizations with compliance requirements under GDPR and other data protection regulations could face legal and financial repercussions if breaches occur due to this vulnerability. The lack of a patch increases the urgency for mitigation to prevent exploitation in environments where the vulnerable ActiveX control is deployed.

European organizations should take immediate steps to mitigate the risk posed by CVE-2025-34128 beyond generic advice. First, conduct an inventory to identify all systems and applications using X360 VideoPlayer ActiveX Control version 2.6. Where possible, disable or unregister the vulnerable ActiveX control to prevent its use. If disabling is not feasible, restrict the execution of ActiveX controls through Group Policy or browser security settings, especially in Internet Explorer or legacy browsers still in use. Implement application whitelisting to block unauthorized or unknown ActiveX controls from running. Employ network-level controls such as web filtering to block access to malicious sites that could host exploit code. Enhance user awareness training focused on phishing and social engineering tactics that might trigger the vulnerability. Monitor endpoint and network logs for unusual activity indicative of exploitation attempts. Engage with X360Soft for updates or patches and plan for rapid deployment once available. Consider isolating legacy systems in segmented network zones to limit potential lateral movement if compromise occurs.