CVE-2025-62926 identifies a Stored Cross-Site Scripting (XSS) vulnerability in the HappyDevs TempTool software, affecting versions up to 1.3.1. The root cause is improper neutralization of input during web page generation, classified under CWE-79. This vulnerability allows an attacker with limited privileges (PR:L) and requiring user interaction (UI:R) to inject malicious scripts that are stored on the server and executed in the context of other users' browsers. The vulnerability has a CVSS 3.1 base score of 6.5, indicating medium severity, with an attack vector of network (AV:N), low attack complexity (AC:L), and scope change (S:C), meaning the vulnerability can affect resources beyond the initially vulnerable component. The impact includes partial loss of confidentiality, integrity, and availability, as attackers can steal session tokens, manipulate displayed content, or perform actions on behalf of users. No patches or known exploits are currently available, but the vulnerability's presence in a web-facing tool used for temperature or environmental monitoring (as implied by the product name) could expose sensitive operational data or user credentials. The vulnerability requires user interaction, such as clicking a crafted link or viewing a malicious page, to trigger the exploit. The lack of patch links suggests that users must implement mitigations proactively until an official fix is released.

For European organizations, the impact of this Stored XSS vulnerability can be significant, especially if TempTool is used in critical infrastructure, manufacturing, or environmental monitoring sectors. Exploitation could lead to unauthorized access to sensitive data, session hijacking, or manipulation of displayed information, potentially disrupting operational decisions. The scope change in the CVSS vector indicates that the vulnerability could affect multiple components or users beyond the initially compromised context, increasing risk. Confidentiality breaches could expose personal or operational data, while integrity violations might lead to false data presentation or unauthorized commands. Availability impact, though partial, could result from malicious scripts causing application crashes or denial of service. Since the vulnerability requires user interaction and limited privileges, insider threats or social engineering could facilitate exploitation. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers often weaponize such vulnerabilities once disclosed.

European organizations should implement the following specific mitigations: 1) Apply strict input validation and output encoding on all user-supplied data within TempTool interfaces to prevent injection of malicious scripts. 2) Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers. 3) Limit user privileges within TempTool to the minimum necessary to reduce the attack surface. 4) Educate users about phishing and social engineering risks to minimize successful user interaction exploitation. 5) Monitor web application logs and network traffic for unusual patterns indicative of XSS attempts. 6) Segregate TempTool deployments in network zones with restricted access to reduce exposure. 7) Prepare to deploy patches promptly once released by HappyDevs. 8) Consider implementing web application firewalls (WAF) with rules targeting XSS payloads specific to TempTool's context. 9) Regularly review and update security policies related to web application security and incident response to address emerging threats.