CVE-2025-63848 is a stored cross-site scripting (XSS) vulnerability identified in SWISH Prolog, an interactive web-based Prolog environment, up to version 2.2.0. The vulnerability arises due to insufficient sanitization of user-supplied input within the web IDE notebook interface, allowing attackers to inject malicious scripts that are stored and subsequently executed in the browsers of users who access the crafted notebook. This type of XSS is particularly dangerous because the malicious payload persists on the server, affecting multiple users over time. The attack vector is network-based (AV:N), requires low attack complexity (AC:L), no privileges (PR:N), but does require user interaction (UI:R), such as opening or interacting with a malicious notebook. The vulnerability impacts confidentiality and integrity (C:L/I:L) but does not affect availability (A:N). The scope is changed (S:C), meaning the vulnerability can affect components beyond the initially vulnerable module, potentially impacting the user's session or data. No patches or known exploits are currently available, but the vulnerability is publicly disclosed and should be addressed promptly. The CWE classification is CWE-79, indicating a classic XSS flaw. This vulnerability could be leveraged to steal session cookies, perform actions on behalf of users, or deliver further malware payloads within the trusted context of the SWISH Prolog web interface.

For European organizations, particularly those involved in software development, research, or education using SWISH Prolog, this vulnerability poses a risk of client-side code execution leading to data leakage or session hijacking. Confidentiality could be compromised if attackers steal sensitive information accessible through the web IDE. Integrity risks include unauthorized actions performed within the user's session. Although availability is not directly impacted, the trustworthiness of the development environment could be undermined, potentially disrupting workflows. The medium severity and requirement for user interaction limit the scope somewhat, but targeted phishing or social engineering could increase exploitation likelihood. Organizations with collaborative environments where multiple users access shared notebooks are at higher risk. The absence of known exploits currently provides a window for proactive mitigation before active attacks emerge.

To mitigate CVE-2025-63848, organizations should implement strict input validation and output encoding within the SWISH Prolog web IDE notebook interface to prevent injection of malicious scripts. Until official patches are released, consider restricting access to the web IDE to trusted users and networks only, and educate users about the risks of opening untrusted notebooks. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts. Regularly monitor logs for suspicious activity related to notebook usage. If feasible, isolate the SWISH Prolog environment in sandboxed or containerized deployments to limit potential impact. Stay informed about updates from SWISH Prolog maintainers and apply security patches promptly once available. Additionally, implement multi-factor authentication and session management best practices to reduce the impact of any potential session hijacking.