CVE-2025-39505 is a high-severity reflected Cross-Site Scripting (XSS) vulnerability identified in the GoodLayers Hotel product, a web-based hotel management or booking solution. The vulnerability arises from improper neutralization of input during web page generation, classified under CWE-79. Specifically, the application fails to adequately sanitize or encode user-supplied input before reflecting it back in the HTTP response, enabling attackers to inject malicious scripts. This reflected XSS can be exploited remotely without authentication (AV:N/PR:N), requiring only user interaction (UI:R), such as clicking a crafted link. The vulnerability impacts confidentiality, integrity, and availability, as malicious scripts can steal session cookies, perform actions on behalf of users, or cause denial of service. The CVSS 3.1 score of 7.1 reflects the high risk posed by this flaw. The vulnerability affects all versions of GoodLayers Hotel up to and including 3.1.4, with no patch currently available. No known exploits are reported in the wild yet. The scope is changed (S:C), indicating that the vulnerability can affect resources beyond the initially vulnerable component, potentially impacting other users or systems. Given the nature of reflected XSS, attackers typically use social engineering to lure victims into clicking malicious URLs, leading to script execution in the victim’s browser context. This can facilitate session hijacking, credential theft, or redirection to malicious sites. Since GoodLayers Hotel is a web-facing application used by hotels for booking and management, exploitation could compromise customer data and hotel operational integrity.

For European organizations, particularly hotels and hospitality businesses using GoodLayers Hotel, this vulnerability poses significant risks. Exploitation could lead to unauthorized access to customer personal data, including payment and booking information, violating GDPR requirements and resulting in regulatory penalties. The integrity of booking systems could be compromised, causing operational disruptions or fraudulent bookings. Additionally, attackers could leverage the XSS flaw to distribute malware or phishing campaigns targeting hotel staff or customers, damaging reputation and trust. The reflected XSS can also be used as a stepping stone for more sophisticated attacks within the network if combined with other vulnerabilities. Given the hospitality sector’s importance in Europe’s economy and the sensitivity of customer data handled, the impact extends beyond individual hotels to affect broader tourism and service sectors. The lack of a patch increases exposure time, emphasizing the need for immediate mitigation.

1. Immediate deployment of Web Application Firewall (WAF) rules to detect and block malicious input patterns targeting the vulnerable parameters in GoodLayers Hotel. 2. Implement strict input validation and output encoding on all user-supplied data reflected in web pages, using context-appropriate encoding (HTML entity encoding, JavaScript escaping). 3. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of XSS attacks. 4. Conduct thorough security testing and code review of the GoodLayers Hotel application to identify and remediate all input handling flaws. 5. Monitor web server logs for suspicious requests indicative of XSS exploitation attempts. 6. Educate hotel staff and users about phishing risks and the dangers of clicking untrusted links. 7. Engage with GoodLayers vendor for timely patch release and apply updates as soon as available. 8. Consider isolating the GoodLayers Hotel application environment to limit lateral movement if compromise occurs. 9. Use HTTPOnly and Secure flags on cookies to mitigate session hijacking risks.