CVE-2025-11945 is a cross-site scripting vulnerability identified in the toeverything AFFiNE product, specifically affecting versions 0.24.0 and 0.24.1. The vulnerability exists in the Avatar Upload Image Endpoint, where insufficient input validation or sanitization allows an attacker to inject malicious scripts. This flaw can be exploited remotely without authentication, although it requires user interaction, such as a victim viewing a crafted avatar or image. The vulnerability enables attackers to execute arbitrary JavaScript in the context of the victim’s browser, potentially leading to session hijacking, credential theft, or other malicious actions. The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:L), user interaction required (UI:P), and limited impact on integrity and availability. The vendor was notified early but has not responded, and no patches or mitigations have been officially released. Public exploits exist, increasing the risk of exploitation. The vulnerability is typical of web applications that handle user-uploaded content without strict validation, making it a classic XSS scenario. Organizations using AFFiNE for collaboration or social interaction features should be aware of this risk and monitor for suspicious activity. The lack of vendor response and patch availability increases the urgency for organizations to implement compensating controls.

For European organizations, this vulnerability could lead to unauthorized script execution in users’ browsers, resulting in session hijacking, data theft, or unauthorized actions performed on behalf of users. This is particularly concerning for organizations relying on AFFiNE for internal collaboration, social networking, or customer engagement, where avatars and user-uploaded images are common. The attack could compromise user credentials or sensitive information, leading to reputational damage and potential regulatory non-compliance under GDPR if personal data is exposed. The medium severity reflects limited impact on system integrity and availability but significant confidentiality risks. Since the exploit requires user interaction, phishing or social engineering could be used to lure victims. The absence of vendor patches means organizations must rely on internal mitigations, increasing operational burden. The presence of a public exploit raises the likelihood of opportunistic attacks, especially in sectors with high-value targets such as finance, government, and critical infrastructure within Europe.

1. Implement strict input validation and sanitization on the Avatar Upload Image Endpoint to reject any scripts or malicious payloads embedded in image metadata or filenames. 2. Restrict allowed file types and enforce content-type validation to only permit safe image formats (e.g., JPEG, PNG). 3. Use Content Security Policy (CSP) headers to limit the execution of inline scripts and reduce the impact of XSS. 4. Deploy Web Application Firewalls (WAF) with rules to detect and block common XSS payloads targeting the upload endpoint. 5. Educate users about phishing and social engineering risks related to clicking on untrusted avatars or images. 6. Monitor logs and network traffic for unusual activity related to avatar uploads or script execution attempts. 7. If possible, sandbox or isolate the avatar rendering component to limit script execution scope. 8. Engage with the vendor or community to encourage patch development and share threat intelligence. 9. Consider temporary disabling avatar upload features if the risk is deemed unacceptable until a patch is available.