CVE-2025-58919 is a medium-severity vulnerability classified under CWE-862 (Missing Authorization) affecting the guihom Wide Banner product up to version 1.0.4. This vulnerability arises from incorrectly configured access control security levels, allowing unauthorized users to perform actions that should be restricted. Specifically, the issue is a Missing Authorization flaw, meaning that the application fails to properly verify whether a user has the necessary permissions before allowing certain operations. According to the CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N), the vulnerability can be exploited remotely over the network without any privileges or user interaction, making it relatively easy to exploit. The impact is limited to integrity loss, with no confidentiality or availability impact. The affected product, Wide Banner by guihom, is a software component presumably used for banner management or display, though detailed usage context is not provided. No patches or known exploits in the wild have been reported as of the publication date (September 26, 2025). The vulnerability's root cause is an access control misconfiguration, which could allow attackers to modify or manipulate banner content or related configurations without authorization, potentially leading to unauthorized content injection or defacement within affected systems.

For European organizations, the impact of CVE-2025-58919 depends largely on the deployment of the guihom Wide Banner product within their IT environments. If used in web portals, marketing platforms, or internal dashboards, unauthorized modification of banner content could lead to misinformation, brand damage, or reputational harm. While the vulnerability does not directly compromise confidentiality or availability, integrity loss can undermine trust in displayed information and may facilitate social engineering or phishing attacks if malicious content is injected. Organizations in sectors with high reliance on digital marketing or customer-facing portals—such as retail, media, and public services—may experience operational disruptions or customer trust issues. Additionally, regulatory compliance frameworks in Europe, such as GDPR, emphasize data integrity and security; unauthorized content manipulation could raise compliance concerns if it leads to misleading information or impacts user data indirectly. The lack of known exploits reduces immediate risk, but the ease of exploitation and network accessibility suggest that threat actors could develop exploits if the product is widely used.

To mitigate CVE-2025-58919, European organizations should first inventory their use of guihom Wide Banner and identify affected versions (up to 1.0.4). Although no official patches are currently available, organizations should implement compensating controls such as restricting network access to the Wide Banner management interfaces using firewalls or VPNs to limit exposure. Implement strict role-based access controls (RBAC) and verify that only authorized personnel have access to banner configuration functions. Conduct thorough access control reviews and penetration testing focused on authorization checks within the Wide Banner application. Monitor logs for unauthorized modification attempts and establish alerting mechanisms for suspicious activities. If possible, isolate the Wide Banner component from critical systems to reduce potential impact. Engage with the vendor for updates or patches and apply them promptly once released. Additionally, consider deploying web application firewalls (WAFs) with custom rules to detect and block unauthorized requests targeting banner management endpoints.