Executive Summary

CVE-2025-10741 is a stored Cross-Site Scripting (XSS) vulnerability in Selleo Mentingo up to version 2025.08.27. It occurs because the application allows uploading SVG files (such as user avatars) without properly sanitizing or validating their content. Since SVG files can contain embedded JavaScript via event handlers like 'onload', an attacker can upload a malicious SVG file with JavaScript code. When a victim views the SVG image, the embedded script executes in their browser, potentially leading to malicious actions such as redirection or credential theft. This vulnerability arises from improper handling of the userAvatar argument in the Profile Picture Handler component, allowing unrestricted upload of SVG files containing malicious scripts. [2, 3, 4]

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Impact Analysis

This vulnerability can impact you by enabling attackers to execute malicious JavaScript in the browsers of users who view the uploaded SVG images. This can lead to credential harvesting, phishing attacks, malware distribution, and social engineering exploits. The malicious SVG files are stored persistently and accessible via presigned URLs, allowing repeated exploitation. Additionally, the unrestricted upload can lead to storage abuse and compromise data integrity by allowing arbitrary files to be stored in image directories. [2, 3, 4]

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Detection Guidance

Detection can focus on identifying malicious SVG uploads and unauthorized file uploads via the userAvatar upload functionality. Since the vulnerability involves uploading SVG files with embedded JavaScript, monitoring uploads for SVG files containing script or event handler attributes (e.g., onload) is key. Network detection can include inspecting HTTP multipart form data for uploads with Content-Type 'image/svg+xml' and analyzing the SVG content for embedded JavaScript. Commands to detect suspicious SVG files could include scanning uploaded files for 'onload' or other event handlers using tools like grep. For example, on the server storing uploaded avatars, run: grep -rilE '<svg[^>]*onload|<script' /path/to/uploaded/files. Additionally, monitoring HTTP requests for file uploads with spoofed Content-Type headers can be done using network capture tools (e.g., tcpdump, Wireshark) filtering for multipart form data with 'image/svg+xml'. [2]

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Mitigation Strategies

Immediate mitigation steps include implementing strict server-side validation of uploaded files beyond MIME type checks. This involves sanitizing SVG files to remove any embedded JavaScript or event handlers before storage or display. Alternatively, disallow SVG uploads entirely or convert SVGs to safe image formats server-side. Restrict upload permissions to trusted users only and monitor uploaded content for malicious payloads. Since the vendor has not provided a fix, consider disabling the user avatar upload feature temporarily or replacing the affected product. Additionally, educate users about the risks and monitor for exploitation attempts. [2, 3, 4]

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