CVE-2025-49891 is a medium severity vulnerability classified under CWE-79, which pertains to Improper Neutralization of Input During Web Page Generation, commonly known as Cross-site Scripting (XSS). This vulnerability affects the riotweb Contact Info Widget, specifically versions up to 2.6.2. The flaw allows an attacker to inject malicious scripts that are stored persistently within the widget's data. When a user accesses the affected web page or widget, the malicious script executes in the context of the victim's browser. The CVSS 3.1 vector indicates that the attack can be performed remotely over the network (AV:N) with low attack complexity (AC:L), but requires high privileges (PR:H) and user interaction (UI:R). The scope is changed (S:C), meaning the vulnerability affects resources beyond the initially vulnerable component. The impact includes low confidentiality, integrity, and availability impacts (C:L/I:L/A:L), suggesting that while the attacker can execute scripts, the overall damage is somewhat limited. No known exploits are currently reported in the wild, and no patches have been linked yet. Stored XSS vulnerabilities like this can be leveraged for session hijacking, phishing, or delivering malware, especially in environments where the Contact Info Widget is widely used and trusted by users.

For European organizations, the impact of this vulnerability can be significant depending on the deployment of riotweb Contact Info Widget within their web infrastructure. Stored XSS can lead to unauthorized access to user sessions, data theft, or manipulation of displayed content, which can undermine user trust and violate data protection regulations such as GDPR. Organizations in sectors like finance, healthcare, and government, which often handle sensitive personal data, are particularly at risk. The requirement for high privileges to exploit the vulnerability somewhat limits the attack surface to insiders or compromised accounts, but the need for user interaction means social engineering could be used to trigger the exploit. Additionally, the scope change indicates that the vulnerability could affect other components or services beyond the widget itself, potentially amplifying the impact. Failure to address this vulnerability promptly could lead to reputational damage, regulatory penalties, and operational disruptions.

To mitigate this vulnerability effectively, European organizations should first identify all instances of the riotweb Contact Info Widget in their environments. Since no official patches are currently linked, organizations should implement strict input validation and output encoding on all user-supplied data within the widget to neutralize malicious scripts. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the risk of XSS exploitation. Additionally, enforce the principle of least privilege to limit high-privilege account access and monitor for unusual activities that may indicate exploitation attempts. Regularly audit and sanitize stored data within the widget to remove any potentially malicious content. Organizations should also educate users about the risks of interacting with untrusted content and maintain up-to-date security awareness training to reduce the likelihood of successful social engineering. Finally, stay alert for vendor updates or patches and apply them promptly once available.