Overview
DeepSeek, commonly used for its robust data aggregation capabilities, has recently been found to have a significant vulnerability in versions R1 through V3.1. This vulnerability, tagged as CVE-2025-26210, exposes users to potential Cross-Site Scripting (XSS) attacks. XSS remains one of the most prevalent security risks on the web, allowing attackers to inject malicious code into web pages viewed by other users. This vulnerability is particularly concerning as it can lead to system compromise or data leakage, making it a high-risk issue that demands immediate attention from all affected parties.
Vulnerability Summary
CVE ID: CVE-2025-26210
Severity: High, with a CVSS score of 8.8
Attack Vector: Network
Privileges Required: None
User Interaction: Required
Impact: Successful exploitation can lead to system compromise and data leakage
Affected Products
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Product | Affected Versions
DeepSeek | R1 through V3.1
How the Exploit Works
The vulnerability is due to insufficient sanitizing of user-supplied inputs in the `run-html-chat.deepseeksvc.com` domain. An attacker can exploit this weakness by sending a specially crafted input to the affected software, which then reflects the malicious script on the web page. When an unsuspecting user interacts with the infected web page, the malicious script gets executed within the context of the victim’s browser, potentially leading to unauthorized actions.
Conceptual Example Code
A potential exploit might look something like this:
GET /chat?nickname=<script>malicious_code_here</script> HTTP/1.1
Host: run-html-chat.deepseeksvc.comIn this example, `` is the injected JavaScript code. When a user views the webpage, the malicious JavaScript code is executed in their browser.
Mitigation
Until a vendor patch is available, the recommended mitigation method is to use a Web Application Firewall (WAF) or Intrusion Detection System (IDS) to detect and block potential XSS attempts. It is also advised to not click on untrusted links and be wary of unexpected behavior on the `run-html-chat.deepseeksvc.com` domain.
