CVE-2025-63916 is a high-severity OS command injection vulnerability affecting MyScreenTools version 2.2.1.0, specifically in the GIF compression tool component. The root cause is improper input sanitization in the CMD() function located in GIFSicleTool\Form_gif_sicle_tool.cs. This function constructs shell commands by concatenating user-supplied file paths directly into command strings executed via cmd.exe without validation or escaping. As a result, an attacker who can supply crafted file paths can inject arbitrary commands that the Windows shell will execute with the same privileges as the user running the application. The vulnerability is classified under CWE-78 (Improper Neutralization of Special Elements used in an OS Command). The CVSS v3.1 base score is 8.1 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N), indicating network attack vector, low attack complexity, requiring privileges but no user interaction, with high confidentiality and integrity impact but no availability impact. Although no public exploits are known yet, the vulnerability poses a significant risk of system compromise, data theft, or further lateral movement within affected environments. The lack of patches currently necessitates immediate compensating controls to mitigate risk.

For European organizations, exploitation of CVE-2025-63916 could lead to unauthorized command execution on systems running MyScreenTools v2.2.1.0, potentially resulting in data breaches, system manipulation, or lateral movement within networks. Given the high confidentiality and integrity impact, sensitive information could be exposed or altered, undermining compliance with GDPR and other data protection regulations. The vulnerability requires local privileges, so initial access vectors may include phishing or insider threats. Organizations relying on this software for image processing or related workflows may face operational disruptions if attackers leverage this flaw. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers often develop exploits rapidly after disclosure. European entities with critical infrastructure or intellectual property managed via affected systems are particularly at risk of espionage or sabotage.

1. Immediately restrict access to MyScreenTools v2.2.1.0 installations, limiting usage to trusted personnel only. 2. Monitor and audit usage logs for suspicious command execution or unexpected file path inputs. 3. Employ application whitelisting and endpoint detection and response (EDR) solutions to detect anomalous cmd.exe invocations originating from MyScreenTools. 4. Implement strict input validation and sanitization at the application level if source code modification is possible, ensuring all file paths are properly escaped or validated before command execution. 5. Use least privilege principles to run MyScreenTools under accounts with minimal permissions to limit potential damage. 6. Network segmentation can help contain any compromise resulting from exploitation. 7. Engage with the software vendor for patches or updates; apply them promptly once available. 8. Educate users on the risks of executing untrusted files or inputs within the application environment. 9. Consider alternative tools without this vulnerability for GIF compression until a fix is released.