CVE-2025-52037 is a stored Cross-Site Scripting (XSS) vulnerability identified in the NotesCMS content management system. The vulnerability specifically affects the /index.php?route=sites page, where the manipulation of the title field in service descriptions allows an attacker to inject malicious scripts that are stored on the server and subsequently executed in the browsers of users who visit the affected page. This vulnerability was confirmed to exist in the source code as of commit 7d821a0f028b0778b245b99ab3d3bff1ac10e2d3 dated May 8, 2024, and was later fixed in commit 95322c5121dbd7070f3bd54f2848079654a0a8ea dated March 31, 2025. The vulnerability falls under CWE-79, which covers improper neutralization of input during web page generation leading to XSS. The attack can be launched remotely without authentication or user interaction, making it a significant risk if exploited. Stored XSS vulnerabilities allow attackers to execute arbitrary JavaScript in the context of the victim's browser, potentially leading to session hijacking, defacement, redirection to malicious sites, or distribution of malware. Although no known exploits are currently reported in the wild, the presence of this vulnerability in a CMS platform that may be used by multiple organizations increases the risk of exploitation once the vulnerability details become widely known. The absence of a CVSS score requires an assessment based on the nature of the vulnerability and its potential impact.

For European organizations using NotesCMS, this vulnerability poses a risk to the confidentiality, integrity, and availability of web applications and their users. Exploitation could lead to theft of user credentials, unauthorized actions performed on behalf of users, and damage to organizational reputation due to defacement or malware distribution. Given that CMS platforms often serve as the backbone for public-facing websites, exploitation could also lead to broader supply chain risks if attackers use the CMS to compromise visitors or connected systems. The impact is particularly critical for organizations handling sensitive user data or providing essential services online. Additionally, regulatory frameworks such as the GDPR impose strict requirements on protecting user data and reporting breaches, so exploitation could result in legal and financial consequences. The remote and unauthenticated nature of the attack vector increases the likelihood of exploitation, especially if organizations have not applied the patch or implemented compensating controls.

Organizations should immediately verify if they are running vulnerable versions of NotesCMS and apply the patch introduced in commit 95322c5121dbd7070f3bd54f2848079654a0a8ea dated March 31, 2025. Beyond patching, it is critical to implement robust input validation and output encoding on all user-supplied data, especially fields that are rendered in web pages such as service description titles. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of potential XSS attacks. Regularly audit and sanitize stored content to detect and remove any malicious scripts that may have been injected prior to patching. Additionally, organizations should monitor web traffic for unusual activity indicative of exploitation attempts and educate developers on secure coding practices to prevent similar vulnerabilities. Web application firewalls (WAFs) configured to detect and block XSS payloads can provide an additional layer of defense while patches are being applied.