CVE-2025-6563 is a medium-severity cross-site scripting (XSS) vulnerability affecting MikroTik RouterOS versions below 7.19.2, specifically in the hotspot functionality. The vulnerability arises due to improper input validation (CWE-20) of the 'dst' parameter, which allows an attacker to inject a 'javascript:' protocol payload. When a victim accesses a maliciously crafted URL and logs into the hotspot, the injected JavaScript executes in the victim's browser context. Additionally, the login POST request can be transformed into a GET request, enabling an attacker to craft a URL that automatically logs in the victim into the attacker's account and triggers the malicious payload without further user interaction. This attack vector leverages the hotspot login mechanism to execute arbitrary scripts, potentially leading to session hijacking, credential theft, or further exploitation within the victim's network environment. The vulnerability does not require privileges or authentication to exploit but does require user interaction (clicking or visiting the malicious URL). The CVSS 4.0 base score is 4.8, reflecting a medium severity with network attack vector, low attack complexity, no privileges required, but user interaction needed, and limited impact on confidentiality and integrity. No known exploits are currently reported in the wild, and no official patches have been linked yet, indicating that mitigation may rely on configuration changes or updates once available.

For European organizations, this vulnerability poses a risk primarily to networks utilizing MikroTik RouterOS hotspots, which are common in small to medium enterprises, public Wi-Fi providers, and some ISP-managed networks. Successful exploitation could allow attackers to execute arbitrary JavaScript in the context of the victim's browser, potentially leading to session hijacking, credential theft, or redirection to malicious sites. This could compromise user privacy and network security, especially in environments where sensitive data is accessed over the hotspot. The automatic login feature abuse increases the risk by reducing the need for user interaction, making phishing or drive-by attacks more effective. While the direct impact on core network infrastructure is limited, the vulnerability could be leveraged as an initial access vector or to escalate attacks within the network. Given the widespread use of MikroTik devices in Europe, particularly in countries with extensive public Wi-Fi deployments and SMB sectors, the threat could affect a broad range of organizations, including hospitality, education, and retail sectors.

1. Immediate mitigation should include disabling or restricting hotspot functionality if not essential, or applying strict input validation and filtering on the 'dst' parameter at the network perimeter or proxy level. 2. Network administrators should monitor for unusual login URLs or traffic patterns indicative of exploitation attempts. 3. Educate users about the risks of clicking on unsolicited or suspicious links, especially when accessing hotspot login pages. 4. Implement network segmentation to limit the impact of compromised hotspot sessions on critical internal resources. 5. Once available, promptly apply official MikroTik RouterOS updates or patches addressing this vulnerability. 6. Consider deploying web application firewalls (WAFs) or intrusion prevention systems (IPS) capable of detecting and blocking malicious JavaScript payloads in hotspot traffic. 7. Review and harden hotspot login page configurations to prevent automatic login URL abuse, including CSRF protections and session management improvements.