CVE-2025-67291 is a stored cross-site scripting (XSS) vulnerability identified in the Media module of Piranha CMS version 12.1. The vulnerability arises from insufficient input validation and output encoding in the Name field of the Media module, allowing attackers to inject arbitrary JavaScript or HTML payloads that are stored persistently in the system. When other users or administrators view the affected content, the malicious script executes in their browsers, potentially enabling session hijacking, credential theft, or unauthorized actions within the CMS context. Stored XSS is particularly dangerous because the payload remains on the server and affects multiple users without requiring repeated exploitation. No CVSS score has been assigned yet, and no patches or exploits are currently documented, but the vulnerability is publicly disclosed and reserved under MITRE. The lack of authentication requirements for injection is not explicitly stated but is implied by the nature of the vulnerability and typical CMS usage patterns. This vulnerability highlights a critical weakness in input sanitization and output encoding in Piranha CMS, which is used for managing web content and media assets. Attackers exploiting this flaw could compromise the integrity and confidentiality of the CMS and its users, potentially leading to broader network compromise or reputational damage.

For European organizations, the impact of CVE-2025-67291 can be significant, especially for those relying on Piranha CMS for their web content management. Successful exploitation could lead to unauthorized script execution in the browsers of site administrators or users, resulting in session hijacking, theft of sensitive information such as authentication tokens or personal data, and unauthorized content manipulation. This can degrade trust in the affected organization's web presence and lead to regulatory consequences under GDPR if personal data is compromised. Additionally, attackers could use the vulnerability as a foothold for further attacks within the organization's network. The persistent nature of stored XSS means that even casual visitors or employees accessing the CMS could be affected, increasing the attack surface. Given the widespread use of CMS platforms in Europe, especially in sectors like government, education, and media, the risk of exploitation could disrupt critical services and damage organizational reputation.

To mitigate CVE-2025-67291, organizations should immediately audit their Piranha CMS installations and restrict access to the Media module to trusted users only until a patch is available. Implement rigorous input validation and output encoding on all user-supplied data, particularly the Name field in the Media module, to prevent injection of malicious scripts. Deploy Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers. Monitor web application logs for suspicious input patterns indicative of XSS attempts. Educate administrators and users about the risks of XSS and encourage cautious handling of content inputs. Once the vendor releases an official patch, apply it promptly. Additionally, consider implementing web application firewalls (WAFs) with rules to detect and block XSS payloads targeting the CMS. Regularly update and harden the CMS environment and conduct security assessments to identify similar vulnerabilities proactively.