CVE-2025-62926 is a stored Cross-site Scripting (XSS) vulnerability classified under CWE-79, affecting HappyDevs TempTool versions up to 1.3.1. The flaw stems from improper neutralization of user-supplied input during web page generation, allowing malicious scripts to be stored persistently within the application. When other users access the affected pages, the injected scripts execute in their browsers, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of the victim. The vulnerability requires an attacker to have low privileges (PR:L) and user interaction (UI:R), such as convincing a user to visit a crafted page or submit data. The CVSS 3.1 base score is 6.5, reflecting a medium severity level with network attack vector (AV:N), low attack complexity (AC:L), and impacts on confidentiality, integrity, and availability (C:L/I:L/A:L). The scope is changed (S:C), meaning the vulnerability affects components beyond the initially vulnerable component. No patches or known exploits are currently available, but the vulnerability is publicly disclosed and should be addressed promptly. The lack of patch links suggests that users must implement mitigations or await official updates from HappyDevs. The vulnerability is particularly relevant for organizations deploying TempTool in web-facing environments where multiple users interact with the application.

For European organizations, exploitation of CVE-2025-62926 could result in unauthorized disclosure of sensitive information, manipulation of data, and disruption of services provided by TempTool. Stored XSS can facilitate session hijacking, enabling attackers to impersonate legitimate users and escalate privileges or access confidential data. This is especially critical for organizations handling personal data under GDPR, as breaches could lead to regulatory penalties and reputational damage. The medium severity indicates a moderate risk, but the changed scope and combined impacts on confidentiality, integrity, and availability elevate the potential consequences. Organizations in sectors such as finance, healthcare, and critical infrastructure that rely on TempTool for operational tasks may face increased risks of targeted attacks. Additionally, the requirement for user interaction means social engineering could be leveraged to maximize impact. Without timely mitigation, attackers could exploit this vulnerability to establish persistent footholds or pivot within networks.

European organizations should implement the following specific mitigations: 1) Apply any official patches or updates from HappyDevs as soon as they become available. 2) In the absence of patches, enforce strict input validation on all user-supplied data to ensure that scripts or HTML tags are sanitized before storage or rendering. 3) Implement robust output encoding/escaping mechanisms on all dynamic content to prevent script execution in browsers. 4) Restrict user privileges to the minimum necessary to reduce the likelihood of malicious input submission. 5) Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts. 6) Conduct regular security audits and penetration testing focusing on web application inputs and outputs. 7) Educate users about phishing and social engineering risks to reduce the chance of successful exploitation requiring user interaction. 8) Monitor web application logs for unusual input patterns or script injections. 9) Consider deploying Web Application Firewalls (WAFs) with rules targeting XSS attack signatures as an interim protective measure. These steps collectively reduce the attack surface and mitigate the risk until a permanent fix is applied.