Overview
This blog post discusses the details of a serious vulnerability, CVE-2025-56515, identified in the Fiora Chat Application version 1.0.0. The flaw lies within the user avatar upload functionality, which allows for the upload and storage of malicious SVG files. This vulnerability is particularly critical as it can lead to the execution of arbitrary JavaScript, enabling attackers to steal user sessions and cookies, and perform unauthorized actions on behalf of users viewing affected profiles. This poses a significant threat to both users and organizations, potentially leading to system compromise or data leakage.
Vulnerability Summary
CVE ID: CVE-2025-56515
Severity: High (8.8 CVSS Severity Score)
Attack Vector: Remote
Privileges Required: None
User Interaction: Required
Impact: Potential system compromise or data leakage
Affected Products
Escape the Surveillance Era
Most apps won’t tell you the truth.
They’re part of the problem.
Phone numbers. Emails. Profiles. Logs.
It’s all fuel for surveillance.
Ameeba Chat gives you a way out.
- • No phone number
- • No email
- • No personal info
- • Anonymous aliases
- • End-to-end encrypted
Chat without a trace.
Product | Affected Versions
Fiora Chat Application | 1.0.0
How the Exploit Works
The vulnerability arises from the application’s failure to validate SVG file content during the user avatar upload process. Attackers can exploit this flaw by embedding foreignObject elements containing iframe tags and JavaScript event handlers (onmouseover) into SVG files. These malicious files are then uploaded and stored within the application. When these SVG files are rendered, they execute arbitrary JavaScript which can lead to unauthorized actions being performed, session theft, and cookie theft.
Conceptual Example Code
Here is a conceptual example of how the vulnerability might be exploited. This is a sample of a crafted SVG file containing malicious JavaScript:
<svg xmlns="http://www.w3.org/2000/svg">
<foreignObject width="100%" height="100%">
<body xmlns="http://www.w3.org/1999/xhtml">
<iframe src="javascript:alert(document.cookie)"></iframe>
</body>
</foreignObject>
</svg>In this example, when the SVG file is rendered by the Fiora Chat Application, it would execute the JavaScript contained within the iframe, which in this case would display an alert with the user’s cookies.
Mitigation Guidance
Users of Fiora Chat Application 1.0.0 are strongly recommended to apply the vendor’s patch to mitigate this vulnerability. In the absence of a patch, the use of a Web Application Firewall (WAF) or Intrusion Detection System (IDS) is recommended as a temporary mitigation measure until the patch can be applied.
