CVE-2025-11278 is a cross-site scripting (XSS) vulnerability identified in the AllMon2 component of AllStarLink Supermon versions 6.0, 6.1, and 6.2. This vulnerability allows remote attackers to inject malicious scripts into the web interface without requiring authentication, though user interaction is necessary to trigger the exploit. The vulnerability arises from insufficient input validation or output encoding in the affected component, enabling attackers to execute arbitrary JavaScript in the context of the victim's browser. This can lead to session hijacking, defacement, or redirection to malicious sites, impacting the integrity and user trust of the application. The product is no longer maintained or supported by the vendor, and no patches or mitigations have been released. The vulnerability was publicly disclosed on October 5, 2025, with a CVSS v4.0 base score of 5.3, indicating a medium severity level. No known exploits have been observed in the wild yet, but the public disclosure and lack of vendor response increase the risk of exploitation. The affected software is primarily used in amateur radio communities for monitoring and managing AllStarLink nodes, which may limit the scope but still presents a risk to organizations relying on this infrastructure.

For European organizations, the impact of CVE-2025-11278 depends on their use of AllStarLink Supermon software. Organizations involved in amateur radio, emergency communication networks, or hobbyist groups using this software may face risks of session hijacking, unauthorized actions, or data manipulation via XSS attacks. Although the vulnerability does not directly compromise system confidentiality or availability, it undermines the integrity of user sessions and could facilitate further social engineering or phishing attacks. The lack of vendor support and patches increases the risk exposure, as affected systems remain vulnerable indefinitely. Additionally, compromised nodes could be leveraged as pivot points for broader network attacks or misinformation campaigns, particularly in critical communication infrastructures. European entities relying on these systems without adequate isolation or monitoring may experience reputational damage or operational disruptions.

Given the absence of vendor patches, European organizations should implement compensating controls to mitigate CVE-2025-11278. These include: 1) Isolating AllStarLink Supermon servers from public networks using firewalls or VPNs to restrict access to trusted users only. 2) Employing web application firewalls (WAFs) with custom rules to detect and block XSS payloads targeting the AllMon2 interface. 3) Encouraging users to employ modern browsers with built-in XSS protection and disabling unnecessary scripting where feasible. 4) Monitoring logs and network traffic for suspicious activity indicative of attempted XSS exploitation. 5) Considering migration to alternative, actively maintained monitoring tools or newer versions if available. 6) Educating users about the risks of clicking untrusted links or executing scripts within the AllStarLink environment. 7) Regularly backing up configuration and data to enable recovery if compromise occurs. These targeted measures go beyond generic advice by focusing on network segmentation, user education, and proactive detection tailored to the specific legacy software environment.