CVE-2017-9516 in Craft
Summary
by MITRE
Craft CMS before 2.6.2982 allows for a potential XSS attack vector by uploading a malicious SVG file.
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Analysis
by VulDB Data Team • 08/24/2025
The vulnerability identified as CVE-2017-9516 affects Craft CMS versions prior to 2.6.2982 and represents a cross-site scripting vulnerability that arises from improper handling of SVG file uploads. This issue stems from the application's failure to adequately sanitize SVG content during the file upload process, creating an attack surface where malicious actors can inject harmful scripts into the system. The vulnerability specifically targets the content management system's media handling capabilities, where SVG files are processed and stored without sufficient validation mechanisms to prevent the execution of malicious code within the markup.
The technical flaw manifests when Craft CMS processes SVG files that contain embedded script tags or malicious JavaScript code within their markup structure. SVG files, by design, support scripting and interactive elements, which makes them inherently more dangerous than traditional image formats. When the CMS fails to properly validate or sanitize the SVG content, it allows attackers to upload files containing malicious payloads that can execute when the SVG is rendered or accessed within the application's interface. This processing occurs during the upload phase, where the system does not adequately filter or strip potentially dangerous elements from the SVG file structure. The vulnerability falls under the CWE-79 category of Cross-Site Scripting, specifically representing a stored XSS attack vector where malicious code is permanently stored on the server and executed when users interact with the compromised content.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities including session hijacking, data exfiltration, and privilege escalation within the CMS environment. An attacker who successfully exploits this vulnerability can potentially gain unauthorized access to user sessions, steal sensitive information, or manipulate content within the CMS. The attack vector is particularly concerning because SVG files are commonly used for logos, icons, and other graphical elements in web applications, making them a frequent upload target. The vulnerability affects not only the administrators but also regular users who may inadvertently trigger the malicious code when viewing uploaded SVG content within the CMS interface or when the files are displayed on public-facing websites. This issue can be exploited through the CMS's media management system, where users with appropriate permissions can upload files, or through more sophisticated attacks that leverage the vulnerability in automated exploitation frameworks.
Organizations affected by this vulnerability should immediately implement mitigations including updating to Craft CMS version 2.6.2982 or later, which includes proper SVG sanitization mechanisms. Additional protective measures should involve implementing strict file type validation for uploads, configuring web application firewalls to detect and block malicious SVG content, and establishing comprehensive monitoring for unauthorized file uploads. The mitigation strategy should also include regular security audits of uploaded content and implementation of content security policies that prevent script execution within SVG files. From an ATT&CK framework perspective, this vulnerability aligns with techniques such as T1059.007 for scripting languages and T1566 for social engineering, as attackers may use the XSS capability to establish persistent access. Organizations should also consider implementing principle of least privilege access controls and regular security training for CMS administrators to reduce the risk of exploitation. The vulnerability demonstrates the importance of proper input validation and output encoding in web applications, particularly when handling rich media formats that support scripting capabilities.