CVE-2025-62024 identifies a Cross-site Scripting (XSS) vulnerability in the Pie Calendar web application developed by Jonathan Jernigan, affecting versions up to and including 1.2.9. The vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, which allows attackers to inject malicious scripts that execute in the context of other users' browsers. The CVSS 3.1 base score is 6.5 (medium), reflecting that the attack vector is network-based (AV:N), with low attack complexity (AC:L), but requiring privileges (PR:L) and user interaction (UI:R). The scope is changed (S:C), indicating that exploitation can affect resources beyond the vulnerable component. The impact metrics show low confidentiality, integrity, and availability impacts (C:L/I:L/A:L), meaning the attacker can partially compromise these aspects but not fully. No known exploits are currently active in the wild, and no patches have been released yet. The vulnerability is typical of reflected or stored XSS, which can be leveraged for session hijacking, phishing, or delivering malware. The lack of patches necessitates immediate mitigation through input sanitization and output encoding at the application level. The vulnerability affects web applications using Pie Calendar, which is a calendar UI component, potentially embedded in various enterprise or public-facing portals.

For European organizations, this vulnerability poses a risk primarily to web applications that integrate Pie Calendar, especially those exposed to external users or with multiple authenticated users. Exploitation could lead to session hijacking, unauthorized actions on behalf of users, or data leakage, impacting confidentiality and integrity. Availability impact is limited but possible if malicious scripts disrupt user sessions or application functionality. Sectors such as finance, government, healthcare, and critical infrastructure that rely on secure web portals may face increased risk due to the sensitive nature of their data and regulatory requirements like GDPR. The medium severity suggests that while the threat is not immediately critical, it can be leveraged as part of a broader attack chain. Organizations lacking timely patching or mitigation controls may experience reputational damage and compliance issues if exploited.

1. Immediately audit all web applications using Pie Calendar to identify affected versions (<=1.2.9). 2. Implement strict input validation and sanitization on all user inputs that interact with the calendar component, ensuring no untrusted data is rendered without proper encoding. 3. Apply context-aware output encoding (e.g., HTML entity encoding) to neutralize any injected scripts. 4. Employ Content Security Policy (CSP) headers to restrict script execution sources and reduce XSS impact. 5. Monitor web application logs for unusual input patterns or error messages indicative of attempted exploitation. 6. Prepare to apply vendor patches or updates as soon as they become available. 7. Educate developers and security teams about secure coding practices related to XSS. 8. Consider using Web Application Firewalls (WAFs) with rules targeting XSS payloads as a temporary protective measure. 9. Conduct penetration testing focused on XSS vectors in affected applications. 10. Review and update incident response plans to handle potential XSS exploitation scenarios.