CVE-2026-49971 in laravel-mediable
Summary
by MITRE • 07/13/2026
Laravel-Mediable before 7.0.0 contains a stored cross-site scripting vulnerability that allows authenticated or anonymous users to execute arbitrary JavaScript by uploading unsanitized SVG files containing embedded scripts in onload event handlers, script tags, or foreignObject elements. Attackers can store persistent XSS payloads in uploaded SVG files that execute with full DOM access when victims open or preview the file, enabling session cookie theft, CSRF token capture, and account takeover.
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Analysis
by VulDB Data Team • 07/13/2026
This vulnerability exists within Laravel-Mediable versions prior to 7.0.0 and represents a critical stored cross-site scripting flaw that can be exploited by both authenticated and anonymous users. The security weakness stems from insufficient input validation and sanitization of uploaded SVG files, allowing malicious actors to embed dangerous JavaScript code within these image formats. The vulnerability specifically targets the handling of SVG files where attackers can include embedded scripts in onload event handlers script tags or foreignObject elements that execute automatically when the file is rendered in a web browser.
The technical implementation of this flaw allows for persistent XSS attacks because SVG files are processed and stored without proper sanitization of potentially dangerous content. When victims access or preview these maliciously crafted files, the embedded JavaScript executes with full DOM access privileges, creating an environment where attackers can perform sophisticated session hijacking operations. This vulnerability directly relates to CWE-79 which describes improper neutralization of input during web page generation and encompasses stored XSS conditions where malicious scripts are permanently stored on the target server.
The operational impact of this vulnerability extends beyond simple script execution as it enables comprehensive attack vectors including session cookie theft through document.cookie access, CSRF token capture for bypassing security measures, and ultimately account takeover capabilities. Attackers can leverage these persistent XSS payloads to maintain long-term access to user accounts, making this vulnerability particularly dangerous in environments where multiple users interact with uploaded content.
Security mitigations for this vulnerability require implementing comprehensive SVG sanitization libraries that strip or neutralize potentially dangerous elements and attributes from uploaded files before storage. Organizations should enforce strict input validation policies that reject SVG files containing script tags or event handlers, while also implementing Content Security Policy headers to limit script execution capabilities. Additionally, the recommended remediation involves upgrading to Laravel-Mediable version 7.0.0 or later where proper sanitization mechanisms have been implemented. The ATT&CK framework categorizes this vulnerability under T1531 which describes Establishing Persistence through Web Shell creation, and T1566 which covers Spearphishing Attachments, making it a significant concern for enterprise security teams implementing defensive measures.
The persistence aspect of this vulnerability means that once malicious SVG files are uploaded and stored on the server, they can continue to affect users indefinitely until proper sanitization is implemented. This characteristic aligns with ATT&CK technique T1203 which describes Exploitation for Client Execution through web-based attacks, where the initial compromise leads to ongoing exploitation of user sessions. Organizations implementing security controls should consider automated scanning of uploaded content and regular vulnerability assessments focusing on file upload validation mechanisms to prevent successful exploitation of this class of vulnerabilities.