Overview
CVE-2025-63872 details a Cross-Site Scripting (XSS) vulnerability discovered in DeepSeek V3.2. This vulnerability allows attackers to inject and execute arbitrary JavaScript code within the context of the DeepSeek application through specially crafted SVG (Scalable Vector Graphics) content generated by the model. Because DeepSeek does not properly sanitize or validate SVG output, malicious actors can leverage this flaw to potentially compromise user accounts, steal sensitive information, or perform unauthorized actions.
Technical Details
The vulnerability resides in the processing of SVG content generated by the DeepSeek V3.2 model. If a user prompts the model to generate an image in SVG format, and the prompt contains a carefully constructed payload that includes JavaScript code, the model may inadvertently output SVG code containing the malicious script. When a user views or interacts with this malformed SVG, the embedded JavaScript executes within the user’s browser, allowing the attacker to perform XSS attacks.
Specifically, SVG supports the embedding of JavaScript through tags such as <script> and event attributes like onload. An attacker can exploit this by injecting these elements into the SVG output generated by DeepSeek.
CVSS Analysis
As of the publication date of this article, a CVSS score has not been assigned to CVE-2025-63872. Given the potential for arbitrary JavaScript execution, a preliminary assessment would suggest a severity rating of Medium to High depending on the scope of the attack and the privileges available to the attacker. A full CVSS analysis should be performed by the DeepSeek team or a security research organization to properly quantify the risk.
The main determining factors will include:
- Attack Vector: The ease with which the vulnerability can be exploited.
- Attack Complexity: The technical skill required to exploit the vulnerability.
- User Interaction: Whether user interaction is required for successful exploitation.
- Scope: Whether the vulnerability affects only the vulnerable component or other components as well.
Possible Impact
The exploitation of this XSS vulnerability could have significant consequences:
- Account Compromise: Attackers could potentially steal user credentials and gain unauthorized access to accounts.
- Data Theft: Sensitive information displayed within the DeepSeek application could be exfiltrated.
- Malware Distribution: Attackers could inject malicious code that redirects users to phishing sites or distributes malware.
- Defacement: The DeepSeek interface could be defaced or manipulated to display misleading information.
- Denial of Service: JavaScript could be used to crash or overload the user’s browser, leading to a denial of service.
Mitigation and Patch Steps
To address CVE-2025-63872, the following mitigation and patch steps are recommended:
- Input Sanitization: Implement rigorous input sanitization to filter out potentially malicious code from user prompts before they are processed by the model.
- Output Encoding: Encode SVG output to prevent the interpretation of malicious code by the browser. Use appropriate encoding functions to escape special characters.
- Content Security Policy (CSP): Implement a strict Content Security Policy (CSP) to restrict the sources from which JavaScript can be executed. This can help prevent the execution of injected JavaScript code.
- Regular Security Audits: Conduct regular security audits and penetration testing to identify and address vulnerabilities in the DeepSeek application.
- Update DeepSeek: Upgrade to the latest version of DeepSeek as soon as a patch is released by the vendor. This is the most effective way to protect against known vulnerabilities.
- Disable SVG Generation (Temporary): As a temporary measure, consider disabling the ability of the model to generate SVG content until a proper fix is implemented.
