CVE-2025-57940 is a medium-severity Stored Cross-Site Scripting (XSS) vulnerability classified under CWE-79, affecting the 'Append extensions on Pages' product developed by Suresh Kumar Mukhiya. This vulnerability arises from improper neutralization of user input during web page generation, allowing malicious scripts to be stored and executed in the context of a victim's browser when they access the affected pages. The vulnerability impacts versions up to 1.1.2, with no specific version range provided. The CVSS 3.1 base score is 5.9, reflecting a network attack vector (AV:N), low attack complexity (AC:L), but requiring high privileges (PR:H) and user interaction (UI:R). The scope is changed (S:C), indicating that exploitation can affect resources beyond the vulnerable component. The impact includes low confidentiality, integrity, and availability impacts, consistent with typical stored XSS effects such as session hijacking, defacement, or redirection to malicious sites. No known exploits are currently reported in the wild, and no patches or mitigations are linked yet. Stored XSS vulnerabilities are particularly dangerous because the malicious payload is saved on the server and served to multiple users, increasing the attack surface. The requirement for high privileges suggests that an attacker must have some level of authenticated access to inject the payload, limiting the attacker's capabilities but still posing a risk if privileged users are compromised or careless. User interaction is needed for the attack to succeed, meaning victims must visit the compromised pages. The vulnerability affects web applications using this specific extension, which likely integrates with content management or page editing systems.

For European organizations, the impact of CVE-2025-57940 depends on their use of the 'Append extensions on Pages' product. Organizations using this extension in their web infrastructure may face risks of session hijacking, unauthorized actions performed on behalf of users, defacement, or distribution of malware via injected scripts. This can lead to reputational damage, data leakage, and potential regulatory non-compliance under GDPR if personal data is exposed or manipulated. The requirement for high privileges to inject the payload somewhat limits the risk to insider threats or attackers who have already compromised privileged accounts. However, once exploited, the vulnerability can affect multiple users, amplifying the damage. European entities with public-facing web portals or intranet systems using this extension are at risk of targeted attacks, especially if attackers aim to exploit trust relationships within organizations. The medium severity score suggests that while the vulnerability is not critical, it should be addressed promptly to prevent escalation or chaining with other vulnerabilities. The lack of known exploits in the wild provides a window for proactive mitigation before widespread exploitation occurs.

1. Immediate mitigation should include restricting access to the 'Append extensions on Pages' functionality to only trusted and necessary privileged users to reduce the risk of malicious input injection. 2. Implement strict input validation and output encoding on all user-supplied data within the extension to neutralize potentially malicious scripts. 3. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in browsers accessing the affected pages. 4. Monitor logs for unusual activity or attempts to inject scripts via the extension interfaces. 5. If possible, disable or remove the vulnerable extension until a security patch is released. 6. Educate privileged users about the risks of injecting untrusted content and enforce strong authentication and session management controls to prevent account compromise. 7. Regularly review and update web application security configurations and conduct penetration testing focused on XSS vectors. 8. Stay alert for official patches or updates from the vendor and apply them promptly once available.