CVE-2025-11278 is a cross-site scripting (XSS) vulnerability identified in the AllStarLink Supermon product, specifically affecting versions 6.0, 6.1, and 6.2. The vulnerability resides in an unspecified component called AllMon2. XSS vulnerabilities allow attackers to inject malicious scripts into web pages viewed by other users, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of the victim. This particular vulnerability can be exploited remotely without requiring authentication, and only requires user interaction (such as visiting a malicious link or page) to trigger the attack. The CVSS 4.0 base score is 5.3, indicating a medium severity level. The attack vector is network-based with low attack complexity and no privileges required. The vulnerability impacts the confidentiality and integrity of user sessions, with limited impact on availability. The vendor has not responded to early disclosure requests, and the affected product versions are no longer supported, meaning no official patches or mitigations are available. Although no known exploits are currently observed in the wild, public disclosure of the exploit code increases the risk of exploitation by opportunistic attackers. The lack of vendor response and unsupported status of the product complicate remediation efforts, leaving organizations relying on these versions exposed to potential targeted or opportunistic XSS attacks.

For European organizations using AllStarLink Supermon versions 6.0 to 6.2, this vulnerability poses a moderate risk. The XSS flaw can be leveraged to compromise user sessions, steal credentials, or perform unauthorized actions within the Supermon interface, potentially leading to unauthorized access or manipulation of monitoring data. Given that AllStarLink is used primarily in amateur radio and communication monitoring communities, organizations involved in emergency communications, public safety, or critical infrastructure monitoring could face operational disruptions or data integrity issues if attackers exploit this vulnerability. The lack of vendor support and patches increases the risk of prolonged exposure. Additionally, if attackers use this vulnerability as a foothold, it could facilitate lateral movement or further attacks within organizational networks. The impact on confidentiality and integrity could affect trust in communication monitoring systems, and in sensitive environments, this could have cascading effects on operational readiness and response capabilities.

Since the affected AllStarLink Supermon versions are no longer supported and no official patches exist, European organizations should consider the following specific mitigation strategies: 1) Immediate upgrade or migration to supported versions or alternative monitoring solutions that do not contain this vulnerability. 2) Implement strict input validation and output encoding at any web application firewall (WAF) or reverse proxy level to detect and block malicious scripts targeting the Supermon interface. 3) Restrict access to the Supermon web interface to trusted internal networks or VPNs to reduce exposure to remote attackers. 4) Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in browsers accessing the Supermon interface. 5) Conduct regular security awareness training for users to recognize and avoid phishing or malicious links that could trigger XSS attacks. 6) Monitor logs and network traffic for unusual activity indicative of exploitation attempts. 7) If feasible, perform code review or implement custom patches to sanitize inputs within the AllMon2 component, though this requires development resources and expertise. These targeted mitigations go beyond generic advice by focusing on compensating controls and network-level protections given the lack of vendor patches.